Ali A. El‐Solh, MD, MPH

Pneumonia is the second most common infection in nursing home residents after urinary tract infection, and is the most common reason for transfer to the hospital.1 Although it remains difficult to determine the incidence of pneumonia in institutionalized elderly patients, an estimated 4 million cases of nursing homeacquired pneumonia (NHAP) occur annually in the United States and result in more than 600,000 emergency department visits.2 In the past 2 decades, multiple studies have documented the rapid rise in drug resistance among common pathogens responsible for pneumonia in the elderly and the acquisition of multidrug‐resistant organisms in residents of long‐term care facilities.3, 4 Health care practitioners are faced with the dilemma of attempting to limit broad‐spectrum antimicrobial drug use while striving to maximize therapeutic efficacy in individual patients.5 The current practice guidelines for the management of NHAP from various professional societies provide mixed messages on the class of antibiotics for patients requiring hospitalization.2, 68 While the 2000 Canadian and the 2003 Infectious Disease Society of America (IDSA) guidelines advocate a community‐acquired pneumonia‐like approach to therapy, the 2005 American Thoracic Society (ATS)/IDSA guidelines and the 2007 IDSA/ATS guidelines consider drug‐resistant pathogens (DRPs) (ie, methicillin‐resistant Staphylococcus aureus [MRSA] and Pseudomonas aeruginosa) to be major etiologic agents in NHAP and thus the empiric treatment recommendations focus specifically on these pathogens (Table 1).

Given these differences in antibiotic recommendations among the various guidelines, we sought to examine the antimicrobial prescription patterns in hospitalized non‐critically‐ill patients with NHAP in multiple tertiary care facilities vis‐‐vis the population demographics and clinical characteristics.

Methods

Results

A total of 397 subjects with NHAP were included in the study. The mean age of the cohort group was 76.8 13.5 years. Eighty percent had 2 or more chronic diseases. Degenerative nervous system, cardiac, and pulmonary diseases accounted for the majority of underlying comorbidities. Demographic and clinical characteristics of the study population are presented in Table 2. At the time of admission, 17% of patients had received antimicrobial therapy for a respiratory ailment within the last week prior to transfer to an acute care facility. The most commonly prescribed agents at the nursing home were an oral fluoroquinolone (81%), a cephalosporin (14%), or a macrolide (3%).

Of the 397 patients who met the criteria for NHAP, all but 5 patients received antimicrobial therapy. The 3 most commonly used antimicrobial compounds for inpatient treatment were fluoroquinolones (51.4%), ceftriaxone (45.0%), and azithromycin (42.1%). None of the participating hospitals had an antibiotic restriction policy for the use of fluoroquinolones or vancomycin.

Monotherapy was prescribed in 57.4%. Fluoroquinolones represented 79.5% of these cases. The other monotherapy choices included a third‐generation cephalosporin (10.7%), piperacillin/tazobactam (8%), and vancomycin (0.2%). Combination therapy consisted mainly of a macrolide plus a third‐generation cephalosporin (74/168; 44%). Other combination regimens included vancomycin plus piperacillin/tazobactam plus ciprofloxacin (35%), vancomycin plus imipenem plus ciprofloxacin (9%), vancomycin plus piperacillin/tazobactam plus azithromycin (4%), vancomycin plus piperacillin/tazobactam (7%), and piperacillin/tazobactam plus azithromycin (1%). Figure 1 shows the distribution of vancomycin and fluoroquinolones use across the different age groups. While the use of fluoroquinolones (P = 0.76) was comparable between groups, there was a significant trend in prescribing less vancomycin with increasing age (P < 0.001). As for the rest of the antibiotics, there was no difference in the overall use of macrolides (P = 0.53), cephalosporins (P = 0.84), or carbapenems (P = 0.67) among age groups. Clindamycin was only used in 9 (2%) out of 392 patients. None of the patients had an aminoglycoside or a sulfa drug prescribed. We also found no difference in terms of antibiotic choice or use of combination therapy among the 3 hospitals (P = 0.78, and P = 0.52; respectively).

Figure 1

Antibiotic choices were influenced by severity of illness. There was an inverse relationship between PSI classes and the use of either fluoroquinolones or ceftriaxone plus azithromycin (P = 0.02) (Figure 2). Patients with higher acuity of illness were more likely to receive combination regimens that include vancomycin plus piperacillin/tazobactam than those with lower acuity of illness (P < 0.001). Neither the comorbidity index nor the ADL scores had a significant impact on the use of combination therapy (P = 0.49 and P = 0.2; respectively). There was a trend toward association between increasing ADL score and the use of vancomycin plus piperacillin/tazobactam but it did not reach statistical significance (P = 0.06). Of interest, patients who were admitted on the University‐affiliated service were more likely to receive combination therapy than those who were under the care of private service (P < 0.001) (Figure 3). Ceftriaxone plus azithromycin accounted for the majority of combination regimens irrespective of physicians' affiliation.

Figure 2

Figure 3

Overall, there were more patients who received antibiotic therapy in compliance with the 2003 IDSA guidelines6 compared with the 2005 ATS/IDSA guidelines7 (65% vs. 19%, respectively; P < 0.001). A positive correlation was noted between severity of illness and adherence to the 2005 ATS/IDSA antimicrobial recommendations (P = 0.02). However, neither the burden of comorbidities nor the functional status was associated with the use of guidelines (P = 0.76 and P = 0.43; respectively).

Duration of therapy ranged from 3 to 21 days with a median of 8 days. The choice of antibiotics, burden of comorbidities, DNR status, or PSI scores had no correlation with antibiotic duration. Only the presence of bacteremia was associated with more than 8 days of antibiotic duration (P < 0.001) (Figure 4). On average, bacteremic patients received 10.1 3.3 (range, 6‐21) days of antimicrobial therapy compared to 7.8 4.1 (range, 319) days for nonbacteremic cases (P < 0.001). During the course of hospitalization, change in antibiotics occurred in 35 (9%) out of the 392 patients, with the majority of substitutions affecting those who were initially prescribed a regimen that included vancomycin plus piperacillin/tazobactam. In these cases, patients were most commonly switched to fluoroquinolones (n = 20), followed by cephalosporins (n = 11).

Figure 4

Discussion

Our study suggests that antimicrobial selection among hospitalized nursing homes patients with pneumonia is influenced by patients' age, severity of illness, and provider's academic affiliation.

This is the first comprehensive study, to our knowledge, to report on the type, distribution, and pattern of antimicrobials prescribed among institutionalized patients requiring hospital admission. Various treatment regimens have been investigated in the last 2 decades using both retrospective and prospective randomized clinical trials to examine the efficacy and safety of parenteral and oral antibiotics in nursing homes.1316 However, there are no randomized controlled clinical trials for the treatment of hospitalized NHAP on which to base treatment recommendations. For some healthcare providers, the treatment parallels the coverage of patients with community‐acquired pneumonia; for others, broad‐spectrum coverage is the norm. In the absence of validated guidelines, the present investigation shows that prescription patterns varied across demographic and clinical characteristics. Fluoroquinolones were the preferred agents for the initial therapy of NHAP across all age groups, probably because of their single daily dosing, broad spectrum coverage against typical and atypical pathogens, and favorable side effect profile. Conversely, the use of vancomycin tended to decline in older age groups. This decline could be attributed to the need for frequent monitoring of trough levels when venous access can be difficult, lack of oral formulation, or potential toxicity. Further studies are needed to examine the validity of this pattern.

To our knowledge, compliance with guidelines regarding treatment of NHAP has not been previously reported. Despite recent studies suggesting that adherence to community‐acquired pneumonia guidelines resulted in reduced need for hospitalization, shorter stays, and lower mortality,1721 our findings indicated a rather low compliance with the most recently published guidelines. Potential reasons for the low levels of compliance include lack of awareness, time lag for the information to be disseminated in the medical community, lack of endorsement by local opinion leaders, or local barriers to implementation of these guidelines. Unfortunately, little is known about physicians' familiarity and attitude toward NHAP guidelines use. Efforts to improve the effectiveness of pneumonia care will depend on future studies aiming at identifying factors that influence nonadherence.

Severity of illness had a significant influence on the prescription pattern of antimicrobial therapy. As the PSI increased, treatment with a fluoroquinolone or with combination therapy of nonpseudomonal third‐generation cephalosporin plus macrolide was replaced by a broader spectrum of antimicrobial coverage. We believe that healthcare providers' prescriptions may be influenced by the recommendations of the ATS guidelines for the treatment of health care associated pneumonia,7 in which antimicrobial therapy for severely ill patients admitted from long‐term care facilities is directed toward multidrug resistant pathogens. The validity of this practice, however, remains the subject of intense debate,2225 driven by the absence of randomized trials showing improved morbidity and mortality.

Few formal clinical trials exist to guide the length of therapy of hospitalized patients with NHAP. The usual recommendation ranges from 7 to 14 days.16, 26 The median duration of 8 days observed in the current study is consistent with length of therapy advocated in the literature.16 Yet, prolonging antibiotic duration has been suggested when clinical severity of illness is high, comorbid illnesses are multiple, and expected resolution is delayed.27 Arguing against such a practice is evidence from meta‐analysis,28 expert reviews,29 and clinical investigation.30 Prescribing principles are nevertheless unlikely to induce substantial change unless their dissemination and promotion is sustained through intensive continuing educational programs for physicians and pharmacists.3133

Our study has a number of limitations. First, the cohort group described in this investigation consists of institutionalized patients in Western New York and hence the antibiotic prescribing patterns may vary in other locations. Second, we did not have adequate microbial information to fully assess the appropriateness of antimicrobial therapy. Third, the absence of microbial etiology may have resulted in incorrect identification of patients with pneumonia. Further, retrospective data extraction is notoriously imperfect, and pneumonia cases may have been missed because of either coding errors or atypical manifestations. However, we have used strict inclusion criteria in to minimize any potential bias. Fourth, the results of this study describe patterns of antibiotic utilization in the treatment of NHAP but do not provide reasoning for such a practice. The rationale behind these practices can only be discerned by a survey of healthcare providers.

In conclusion, we have observed in this study a poor compliance with the current guidelines for the treatment of NHAP. It is generally accepted that physicians' prescribing habits are influenced by their understanding of the pathophysiology and epidemiology of the infection being treated, as well as the pharmacology and spectrum of available antimicrobials. In the absence of outcome data, translation of this knowledge into practice may be influenced by a number of factors, such as the physician's preference, the academic milieu in which the practice occurs, and more importantly, by the patients' clinical condition.

Pneumonia is the second most common infection in nursing home residents after urinary tract infection, and is the most common reason for transfer to the hospital.1 Although it remains difficult to determine the incidence of pneumonia in institutionalized elderly patients, an estimated 4 million cases of nursing homeacquired pneumonia (NHAP) occur annually in the United States and result in more than 600,000 emergency department visits.2 In the past 2 decades, multiple studies have documented the rapid rise in drug resistance among common pathogens responsible for pneumonia in the elderly and the acquisition of multidrug‐resistant organisms in residents of long‐term care facilities.3, 4 Health care practitioners are faced with the dilemma of attempting to limit broad‐spectrum antimicrobial drug use while striving to maximize therapeutic efficacy in individual patients.5 The current practice guidelines for the management of NHAP from various professional societies provide mixed messages on the class of antibiotics for patients requiring hospitalization.2, 68 While the 2000 Canadian and the 2003 Infectious Disease Society of America (IDSA) guidelines advocate a community‐acquired pneumonia‐like approach to therapy, the 2005 American Thoracic Society (ATS)/IDSA guidelines and the 2007 IDSA/ATS guidelines consider drug‐resistant pathogens (DRPs) (ie, methicillin‐resistant Staphylococcus aureus [MRSA] and Pseudomonas aeruginosa) to be major etiologic agents in NHAP and thus the empiric treatment recommendations focus specifically on these pathogens (Table 1).

Given these differences in antibiotic recommendations among the various guidelines, we sought to examine the antimicrobial prescription patterns in hospitalized non‐critically‐ill patients with NHAP in multiple tertiary care facilities vis‐‐vis the population demographics and clinical characteristics.

Methods

Results

A total of 397 subjects with NHAP were included in the study. The mean age of the cohort group was 76.8 13.5 years. Eighty percent had 2 or more chronic diseases. Degenerative nervous system, cardiac, and pulmonary diseases accounted for the majority of underlying comorbidities. Demographic and clinical characteristics of the study population are presented in Table 2. At the time of admission, 17% of patients had received antimicrobial therapy for a respiratory ailment within the last week prior to transfer to an acute care facility. The most commonly prescribed agents at the nursing home were an oral fluoroquinolone (81%), a cephalosporin (14%), or a macrolide (3%).

Of the 397 patients who met the criteria for NHAP, all but 5 patients received antimicrobial therapy. The 3 most commonly used antimicrobial compounds for inpatient treatment were fluoroquinolones (51.4%), ceftriaxone (45.0%), and azithromycin (42.1%). None of the participating hospitals had an antibiotic restriction policy for the use of fluoroquinolones or vancomycin.

Monotherapy was prescribed in 57.4%. Fluoroquinolones represented 79.5% of these cases. The other monotherapy choices included a third‐generation cephalosporin (10.7%), piperacillin/tazobactam (8%), and vancomycin (0.2%). Combination therapy consisted mainly of a macrolide plus a third‐generation cephalosporin (74/168; 44%). Other combination regimens included vancomycin plus piperacillin/tazobactam plus ciprofloxacin (35%), vancomycin plus imipenem plus ciprofloxacin (9%), vancomycin plus piperacillin/tazobactam plus azithromycin (4%), vancomycin plus piperacillin/tazobactam (7%), and piperacillin/tazobactam plus azithromycin (1%). Figure 1 shows the distribution of vancomycin and fluoroquinolones use across the different age groups. While the use of fluoroquinolones (P = 0.76) was comparable between groups, there was a significant trend in prescribing less vancomycin with increasing age (P < 0.001). As for the rest of the antibiotics, there was no difference in the overall use of macrolides (P = 0.53), cephalosporins (P = 0.84), or carbapenems (P = 0.67) among age groups. Clindamycin was only used in 9 (2%) out of 392 patients. None of the patients had an aminoglycoside or a sulfa drug prescribed. We also found no difference in terms of antibiotic choice or use of combination therapy among the 3 hospitals (P = 0.78, and P = 0.52; respectively).

Figure 1

Antibiotic choices were influenced by severity of illness. There was an inverse relationship between PSI classes and the use of either fluoroquinolones or ceftriaxone plus azithromycin (P = 0.02) (Figure 2). Patients with higher acuity of illness were more likely to receive combination regimens that include vancomycin plus piperacillin/tazobactam than those with lower acuity of illness (P < 0.001). Neither the comorbidity index nor the ADL scores had a significant impact on the use of combination therapy (P = 0.49 and P = 0.2; respectively). There was a trend toward association between increasing ADL score and the use of vancomycin plus piperacillin/tazobactam but it did not reach statistical significance (P = 0.06). Of interest, patients who were admitted on the University‐affiliated service were more likely to receive combination therapy than those who were under the care of private service (P < 0.001) (Figure 3). Ceftriaxone plus azithromycin accounted for the majority of combination regimens irrespective of physicians' affiliation.

Figure 2

Figure 3

Overall, there were more patients who received antibiotic therapy in compliance with the 2003 IDSA guidelines6 compared with the 2005 ATS/IDSA guidelines7 (65% vs. 19%, respectively; P < 0.001). A positive correlation was noted between severity of illness and adherence to the 2005 ATS/IDSA antimicrobial recommendations (P = 0.02). However, neither the burden of comorbidities nor the functional status was associated with the use of guidelines (P = 0.76 and P = 0.43; respectively).

Duration of therapy ranged from 3 to 21 days with a median of 8 days. The choice of antibiotics, burden of comorbidities, DNR status, or PSI scores had no correlation with antibiotic duration. Only the presence of bacteremia was associated with more than 8 days of antibiotic duration (P < 0.001) (Figure 4). On average, bacteremic patients received 10.1 3.3 (range, 6‐21) days of antimicrobial therapy compared to 7.8 4.1 (range, 319) days for nonbacteremic cases (P < 0.001). During the course of hospitalization, change in antibiotics occurred in 35 (9%) out of the 392 patients, with the majority of substitutions affecting those who were initially prescribed a regimen that included vancomycin plus piperacillin/tazobactam. In these cases, patients were most commonly switched to fluoroquinolones (n = 20), followed by cephalosporins (n = 11).

Figure 4

Discussion

Our study suggests that antimicrobial selection among hospitalized nursing homes patients with pneumonia is influenced by patients' age, severity of illness, and provider's academic affiliation.

This is the first comprehensive study, to our knowledge, to report on the type, distribution, and pattern of antimicrobials prescribed among institutionalized patients requiring hospital admission. Various treatment regimens have been investigated in the last 2 decades using both retrospective and prospective randomized clinical trials to examine the efficacy and safety of parenteral and oral antibiotics in nursing homes.1316 However, there are no randomized controlled clinical trials for the treatment of hospitalized NHAP on which to base treatment recommendations. For some healthcare providers, the treatment parallels the coverage of patients with community‐acquired pneumonia; for others, broad‐spectrum coverage is the norm. In the absence of validated guidelines, the present investigation shows that prescription patterns varied across demographic and clinical characteristics. Fluoroquinolones were the preferred agents for the initial therapy of NHAP across all age groups, probably because of their single daily dosing, broad spectrum coverage against typical and atypical pathogens, and favorable side effect profile. Conversely, the use of vancomycin tended to decline in older age groups. This decline could be attributed to the need for frequent monitoring of trough levels when venous access can be difficult, lack of oral formulation, or potential toxicity. Further studies are needed to examine the validity of this pattern.

To our knowledge, compliance with guidelines regarding treatment of NHAP has not been previously reported. Despite recent studies suggesting that adherence to community‐acquired pneumonia guidelines resulted in reduced need for hospitalization, shorter stays, and lower mortality,1721 our findings indicated a rather low compliance with the most recently published guidelines. Potential reasons for the low levels of compliance include lack of awareness, time lag for the information to be disseminated in the medical community, lack of endorsement by local opinion leaders, or local barriers to implementation of these guidelines. Unfortunately, little is known about physicians' familiarity and attitude toward NHAP guidelines use. Efforts to improve the effectiveness of pneumonia care will depend on future studies aiming at identifying factors that influence nonadherence.

Severity of illness had a significant influence on the prescription pattern of antimicrobial therapy. As the PSI increased, treatment with a fluoroquinolone or with combination therapy of nonpseudomonal third‐generation cephalosporin plus macrolide was replaced by a broader spectrum of antimicrobial coverage. We believe that healthcare providers' prescriptions may be influenced by the recommendations of the ATS guidelines for the treatment of health care associated pneumonia,7 in which antimicrobial therapy for severely ill patients admitted from long‐term care facilities is directed toward multidrug resistant pathogens. The validity of this practice, however, remains the subject of intense debate,2225 driven by the absence of randomized trials showing improved morbidity and mortality.

Few formal clinical trials exist to guide the length of therapy of hospitalized patients with NHAP. The usual recommendation ranges from 7 to 14 days.16, 26 The median duration of 8 days observed in the current study is consistent with length of therapy advocated in the literature.16 Yet, prolonging antibiotic duration has been suggested when clinical severity of illness is high, comorbid illnesses are multiple, and expected resolution is delayed.27 Arguing against such a practice is evidence from meta‐analysis,28 expert reviews,29 and clinical investigation.30 Prescribing principles are nevertheless unlikely to induce substantial change unless their dissemination and promotion is sustained through intensive continuing educational programs for physicians and pharmacists.3133

Our study has a number of limitations. First, the cohort group described in this investigation consists of institutionalized patients in Western New York and hence the antibiotic prescribing patterns may vary in other locations. Second, we did not have adequate microbial information to fully assess the appropriateness of antimicrobial therapy. Third, the absence of microbial etiology may have resulted in incorrect identification of patients with pneumonia. Further, retrospective data extraction is notoriously imperfect, and pneumonia cases may have been missed because of either coding errors or atypical manifestations. However, we have used strict inclusion criteria in to minimize any potential bias. Fourth, the results of this study describe patterns of antibiotic utilization in the treatment of NHAP but do not provide reasoning for such a practice. The rationale behind these practices can only be discerned by a survey of healthcare providers.

In conclusion, we have observed in this study a poor compliance with the current guidelines for the treatment of NHAP. It is generally accepted that physicians' prescribing habits are influenced by their understanding of the pathophysiology and epidemiology of the infection being treated, as well as the pharmacology and spectrum of available antimicrobials. In the absence of outcome data, translation of this knowledge into practice may be influenced by a number of factors, such as the physician's preference, the academic milieu in which the practice occurs, and more importantly, by the patients' clinical condition.

Pneumonia is the second most common infection in nursing home residents after urinary tract infection, and is the most common reason for transfer to the hospital.1 Although it remains difficult to determine the incidence of pneumonia in institutionalized elderly patients, an estimated 4 million cases of nursing homeacquired pneumonia (NHAP) occur annually in the United States and result in more than 600,000 emergency department visits.2 In the past 2 decades, multiple studies have documented the rapid rise in drug resistance among common pathogens responsible for pneumonia in the elderly and the acquisition of multidrug‐resistant organisms in residents of long‐term care facilities.3, 4 Health care practitioners are faced with the dilemma of attempting to limit broad‐spectrum antimicrobial drug use while striving to maximize therapeutic efficacy in individual patients.5 The current practice guidelines for the management of NHAP from various professional societies provide mixed messages on the class of antibiotics for patients requiring hospitalization.2, 68 While the 2000 Canadian and the 2003 Infectious Disease Society of America (IDSA) guidelines advocate a community‐acquired pneumonia‐like approach to therapy, the 2005 American Thoracic Society (ATS)/IDSA guidelines and the 2007 IDSA/ATS guidelines consider drug‐resistant pathogens (DRPs) (ie, methicillin‐resistant Staphylococcus aureus [MRSA] and Pseudomonas aeruginosa) to be major etiologic agents in NHAP and thus the empiric treatment recommendations focus specifically on these pathogens (Table 1).

Given these differences in antibiotic recommendations among the various guidelines, we sought to examine the antimicrobial prescription patterns in hospitalized non‐critically‐ill patients with NHAP in multiple tertiary care facilities vis‐‐vis the population demographics and clinical characteristics.

Methods

Results

A total of 397 subjects with NHAP were included in the study. The mean age of the cohort group was 76.8 13.5 years. Eighty percent had 2 or more chronic diseases. Degenerative nervous system, cardiac, and pulmonary diseases accounted for the majority of underlying comorbidities. Demographic and clinical characteristics of the study population are presented in Table 2. At the time of admission, 17% of patients had received antimicrobial therapy for a respiratory ailment within the last week prior to transfer to an acute care facility. The most commonly prescribed agents at the nursing home were an oral fluoroquinolone (81%), a cephalosporin (14%), or a macrolide (3%).

Of the 397 patients who met the criteria for NHAP, all but 5 patients received antimicrobial therapy. The 3 most commonly used antimicrobial compounds for inpatient treatment were fluoroquinolones (51.4%), ceftriaxone (45.0%), and azithromycin (42.1%). None of the participating hospitals had an antibiotic restriction policy for the use of fluoroquinolones or vancomycin.

Monotherapy was prescribed in 57.4%. Fluoroquinolones represented 79.5% of these cases. The other monotherapy choices included a third‐generation cephalosporin (10.7%), piperacillin/tazobactam (8%), and vancomycin (0.2%). Combination therapy consisted mainly of a macrolide plus a third‐generation cephalosporin (74/168; 44%). Other combination regimens included vancomycin plus piperacillin/tazobactam plus ciprofloxacin (35%), vancomycin plus imipenem plus ciprofloxacin (9%), vancomycin plus piperacillin/tazobactam plus azithromycin (4%), vancomycin plus piperacillin/tazobactam (7%), and piperacillin/tazobactam plus azithromycin (1%). Figure 1 shows the distribution of vancomycin and fluoroquinolones use across the different age groups. While the use of fluoroquinolones (P = 0.76) was comparable between groups, there was a significant trend in prescribing less vancomycin with increasing age (P < 0.001). As for the rest of the antibiotics, there was no difference in the overall use of macrolides (P = 0.53), cephalosporins (P = 0.84), or carbapenems (P = 0.67) among age groups. Clindamycin was only used in 9 (2%) out of 392 patients. None of the patients had an aminoglycoside or a sulfa drug prescribed. We also found no difference in terms of antibiotic choice or use of combination therapy among the 3 hospitals (P = 0.78, and P = 0.52; respectively).

Figure 1

Antibiotic choices were influenced by severity of illness. There was an inverse relationship between PSI classes and the use of either fluoroquinolones or ceftriaxone plus azithromycin (P = 0.02) (Figure 2). Patients with higher acuity of illness were more likely to receive combination regimens that include vancomycin plus piperacillin/tazobactam than those with lower acuity of illness (P < 0.001). Neither the comorbidity index nor the ADL scores had a significant impact on the use of combination therapy (P = 0.49 and P = 0.2; respectively). There was a trend toward association between increasing ADL score and the use of vancomycin plus piperacillin/tazobactam but it did not reach statistical significance (P = 0.06). Of interest, patients who were admitted on the University‐affiliated service were more likely to receive combination therapy than those who were under the care of private service (P < 0.001) (Figure 3). Ceftriaxone plus azithromycin accounted for the majority of combination regimens irrespective of physicians' affiliation.

Figure 2

Figure 3

Overall, there were more patients who received antibiotic therapy in compliance with the 2003 IDSA guidelines6 compared with the 2005 ATS/IDSA guidelines7 (65% vs. 19%, respectively; P < 0.001). A positive correlation was noted between severity of illness and adherence to the 2005 ATS/IDSA antimicrobial recommendations (P = 0.02). However, neither the burden of comorbidities nor the functional status was associated with the use of guidelines (P = 0.76 and P = 0.43; respectively).

Duration of therapy ranged from 3 to 21 days with a median of 8 days. The choice of antibiotics, burden of comorbidities, DNR status, or PSI scores had no correlation with antibiotic duration. Only the presence of bacteremia was associated with more than 8 days of antibiotic duration (P < 0.001) (Figure 4). On average, bacteremic patients received 10.1 3.3 (range, 6‐21) days of antimicrobial therapy compared to 7.8 4.1 (range, 319) days for nonbacteremic cases (P < 0.001). During the course of hospitalization, change in antibiotics occurred in 35 (9%) out of the 392 patients, with the majority of substitutions affecting those who were initially prescribed a regimen that included vancomycin plus piperacillin/tazobactam. In these cases, patients were most commonly switched to fluoroquinolones (n = 20), followed by cephalosporins (n = 11).

Figure 4

Discussion

Our study suggests that antimicrobial selection among hospitalized nursing homes patients with pneumonia is influenced by patients' age, severity of illness, and provider's academic affiliation.

This is the first comprehensive study, to our knowledge, to report on the type, distribution, and pattern of antimicrobials prescribed among institutionalized patients requiring hospital admission. Various treatment regimens have been investigated in the last 2 decades using both retrospective and prospective randomized clinical trials to examine the efficacy and safety of parenteral and oral antibiotics in nursing homes.1316 However, there are no randomized controlled clinical trials for the treatment of hospitalized NHAP on which to base treatment recommendations. For some healthcare providers, the treatment parallels the coverage of patients with community‐acquired pneumonia; for others, broad‐spectrum coverage is the norm. In the absence of validated guidelines, the present investigation shows that prescription patterns varied across demographic and clinical characteristics. Fluoroquinolones were the preferred agents for the initial therapy of NHAP across all age groups, probably because of their single daily dosing, broad spectrum coverage against typical and atypical pathogens, and favorable side effect profile. Conversely, the use of vancomycin tended to decline in older age groups. This decline could be attributed to the need for frequent monitoring of trough levels when venous access can be difficult, lack of oral formulation, or potential toxicity. Further studies are needed to examine the validity of this pattern.

To our knowledge, compliance with guidelines regarding treatment of NHAP has not been previously reported. Despite recent studies suggesting that adherence to community‐acquired pneumonia guidelines resulted in reduced need for hospitalization, shorter stays, and lower mortality,1721 our findings indicated a rather low compliance with the most recently published guidelines. Potential reasons for the low levels of compliance include lack of awareness, time lag for the information to be disseminated in the medical community, lack of endorsement by local opinion leaders, or local barriers to implementation of these guidelines. Unfortunately, little is known about physicians' familiarity and attitude toward NHAP guidelines use. Efforts to improve the effectiveness of pneumonia care will depend on future studies aiming at identifying factors that influence nonadherence.

Severity of illness had a significant influence on the prescription pattern of antimicrobial therapy. As the PSI increased, treatment with a fluoroquinolone or with combination therapy of nonpseudomonal third‐generation cephalosporin plus macrolide was replaced by a broader spectrum of antimicrobial coverage. We believe that healthcare providers' prescriptions may be influenced by the recommendations of the ATS guidelines for the treatment of health care associated pneumonia,7 in which antimicrobial therapy for severely ill patients admitted from long‐term care facilities is directed toward multidrug resistant pathogens. The validity of this practice, however, remains the subject of intense debate,2225 driven by the absence of randomized trials showing improved morbidity and mortality.

Few formal clinical trials exist to guide the length of therapy of hospitalized patients with NHAP. The usual recommendation ranges from 7 to 14 days.16, 26 The median duration of 8 days observed in the current study is consistent with length of therapy advocated in the literature.16 Yet, prolonging antibiotic duration has been suggested when clinical severity of illness is high, comorbid illnesses are multiple, and expected resolution is delayed.27 Arguing against such a practice is evidence from meta‐analysis,28 expert reviews,29 and clinical investigation.30 Prescribing principles are nevertheless unlikely to induce substantial change unless their dissemination and promotion is sustained through intensive continuing educational programs for physicians and pharmacists.3133

Our study has a number of limitations. First, the cohort group described in this investigation consists of institutionalized patients in Western New York and hence the antibiotic prescribing patterns may vary in other locations. Second, we did not have adequate microbial information to fully assess the appropriateness of antimicrobial therapy. Third, the absence of microbial etiology may have resulted in incorrect identification of patients with pneumonia. Further, retrospective data extraction is notoriously imperfect, and pneumonia cases may have been missed because of either coding errors or atypical manifestations. However, we have used strict inclusion criteria in to minimize any potential bias. Fourth, the results of this study describe patterns of antibiotic utilization in the treatment of NHAP but do not provide reasoning for such a practice. The rationale behind these practices can only be discerned by a survey of healthcare providers.

In conclusion, we have observed in this study a poor compliance with the current guidelines for the treatment of NHAP. It is generally accepted that physicians' prescribing habits are influenced by their understanding of the pathophysiology and epidemiology of the infection being treated, as well as the pharmacology and spectrum of available antimicrobials. In the absence of outcome data, translation of this knowledge into practice may be influenced by a number of factors, such as the physician's preference, the academic milieu in which the practice occurs, and more importantly, by the patients' clinical condition.