Nephrology

In the United States, 5.9% of the population has diabetes mellitus, and 800,000 people are given a diagnosis of this disease every year.¹ Between 1990 and 1998 the age-adjusted prevalence of diabetes rose by 33%.² It continues to affect younger people; since 1990 the United States experienced a 70% increase in the number of individuals aged between 30 and 39 years who were given the diagnosis of this chronic disease. Diabetes is the single most common cause of end-stage renal disease (ESRD), and ESRD rates continue to increase because of higher prevalence and longer life expectancies for people with type 2 diabetes.

Prevalence

Without interventions, 20% to 40% of type 2 patients with microalbuminuria eventually develop overt nephropathy, and it is estimated that 20% will have ESRD after 20 years.³ The clinical impact is seen in the frequency of treatment for new cases of ESRD from 1984 to 1996. It increased by 44% among persons younger than 45 years with diabetes, by 213% among those 45 to 64 years, by 405% among persons 65 to 74 years, and by 644% among those 75 years and older.⁴ Appropriate treatment can substantially reduce the incidence of nephropathy and the risk of acquiring other diabetes-related complications.^5,6 However, the benefits of effective diabetes treatment will only be fully realized if preventive therapy is effectively integrated into clinical practice. Since the vast majority of patients with diabetes receive their care from a primary care physician, the focal point for the improvement of diabetes care should be the primary care office.⁷

Screening

Two articles in this month’s issue of JFP shed additional light on screening for microalbuminuria among people with diabetes. Scheid and colleagues⁸ systematically review the literature for evidence that screening for microalbuminuria prevents nephropathy in patients with diabetes. It is a short list of articles. The authors found no controlled trials of screening to prevent progression to nephropathy. It has only been in the last several years that good evidence has become available that treating microalbuminuria prevents progression to nephropathy in both type 1 and type 2 diabetes. The authors are asking a 2-part question: (1) How effective is screening for the detection of microalbuminuria? and (2) How effective is the treatment of microalbuminuria in the prevention of nephropathy? Evaluation of the evidence behind screening is incomplete without both answers. Although treatment of microalbuminuria is effective, the mechanics behind screening are complex. The authors raise an interesting challenge regarding the usefulness of repeating microalbumin tests to confirm the diagnosis of microalbuminuria. Repeating this test to reduce the error introduced by diurnal variation in the urine sample, as recommended by the American Diabetes Association, does not necessarily increase the predictive value. Although semiquantitative tests vary in accuracy with the specific gravity of urine (a variation that is substantially corrected for with quantitative tests), the authors note that the practical advantages of semiquantitative tests may outweigh their disadvantages. They call for a trial of different screening methodologies. They also remind us that much of what we do is based on expert opinion and is improved by closer evaluation of the specific recommendations.

The article by Hueston and colleagues⁹ is a sobering reminder of how, even in our training sites, we fail to institute clinical recommendations. In the 2 practices examined in this study, the rate of microalbumin testing was low. This was not because physicians were selectively screening only patients most likely to benefit and skipping those with proteinuria in whom testing may be less beneficial. Patients were not screened regardless of their risk and were often not started on angiotensin-converting enzyme (ACE) inhibitor therapy even with a positive screening result. I would suggest that the power of the study is misleading, since performing a microalbumin test is more likely a physician behavior than a patient characteristic. The likelihood of a patient having a microalbumin screen is probably nested within individual physician behavior and perhaps nested further within the 2 practices studied because of practice resources, laboratory availability, and similar practice patterns among faculty. It is also difficult to generalize how widespread this problem is. Still, it is an important step forward to recognize that clinical recommendations for microalbumin screening are not being followed within 2 residency practices and perhaps many more.

Preventive services

Of course, identifying the problem is only the first step. We must next take responsibility for improving the delivery of high-quality preventive services. Unfortunately this is not likely to be an easy task, such as the proposed consideration of recommending that everyone with diabetes be placed on an ACE inhibitor. There is very little evidence that patients with type 1 or type 2 diabetes who do not have hypertension and do not have microalbuminuria receive any patient-oriented improvement from long-term administration of ACE inhibitors. To suggest that population-based treatment of people with diabetes with ACE inhibitors would be cheaper or easier misses the point that as physicians we provide the best care for individuals and will (almost) never support the potential sacrifice of an individual’s well-being for societal benefits. Although streamlining the information flow of newly established evidence to daily practice will help, improved delivery of care will ultimately occur one physician at a time. I believe that the authors’ statement that “Since physicians do not screen reliably for fatal diseases with screening modalities that have been available for decades, it is unlikely that their behavior is likely to improve,” regrettably overlooks the enormous successes that have occurred in lipid management, cervical cancer, and breast cancer. Translating the latest recommendations into current practice will always be a struggle. But one of the strengths of family physicians is the continuing personal care that we can provide. Family physicians will not abandon the initiation of new preventive services and should not compromise personal care by treating populations at the expense of individuals.

The practice of prevention is always changing. It is a sign of strength that we can identify problems within our practices, and a justification of the confidence of our patients that we can correct those problems. Although expert recommendations flourish, it is essential for primary care physicians to examine all the elements of screening programs to ensure that the evidence demonstrates both effective and efficient care delivery. Diabetes preventive care now also entails close control of hypertension and cholesterol, periodic foot and eye examinations, and microalbumin testing.

Recognizing these new demands, the American Diabetes Association has recently announced the initiation of the Diabetic Cardiovascular Disease Initiative to emphasize the importance of cardiovascular disease prevention, and the American Medical Association, the National Council on Quality Assurance, and the Joint Commission on Health Care Accreditation have announced new performance measures for diabetes care that include a wide variety of important disease prevention practices.¹⁰ Family physicians, perhaps more than any other specialty, are continuing to discover better ways to deliver preventive care effectively and efficiently to our patients with diabetes.

In the United States, 5.9% of the population has diabetes mellitus, and 800,000 people are given a diagnosis of this disease every year.¹ Between 1990 and 1998 the age-adjusted prevalence of diabetes rose by 33%.² It continues to affect younger people; since 1990 the United States experienced a 70% increase in the number of individuals aged between 30 and 39 years who were given the diagnosis of this chronic disease. Diabetes is the single most common cause of end-stage renal disease (ESRD), and ESRD rates continue to increase because of higher prevalence and longer life expectancies for people with type 2 diabetes.

Prevalence

Without interventions, 20% to 40% of type 2 patients with microalbuminuria eventually develop overt nephropathy, and it is estimated that 20% will have ESRD after 20 years.³ The clinical impact is seen in the frequency of treatment for new cases of ESRD from 1984 to 1996. It increased by 44% among persons younger than 45 years with diabetes, by 213% among those 45 to 64 years, by 405% among persons 65 to 74 years, and by 644% among those 75 years and older.⁴ Appropriate treatment can substantially reduce the incidence of nephropathy and the risk of acquiring other diabetes-related complications.^5,6 However, the benefits of effective diabetes treatment will only be fully realized if preventive therapy is effectively integrated into clinical practice. Since the vast majority of patients with diabetes receive their care from a primary care physician, the focal point for the improvement of diabetes care should be the primary care office.⁷

Screening

Two articles in this month’s issue of JFP shed additional light on screening for microalbuminuria among people with diabetes. Scheid and colleagues⁸ systematically review the literature for evidence that screening for microalbuminuria prevents nephropathy in patients with diabetes. It is a short list of articles. The authors found no controlled trials of screening to prevent progression to nephropathy. It has only been in the last several years that good evidence has become available that treating microalbuminuria prevents progression to nephropathy in both type 1 and type 2 diabetes. The authors are asking a 2-part question: (1) How effective is screening for the detection of microalbuminuria? and (2) How effective is the treatment of microalbuminuria in the prevention of nephropathy? Evaluation of the evidence behind screening is incomplete without both answers. Although treatment of microalbuminuria is effective, the mechanics behind screening are complex. The authors raise an interesting challenge regarding the usefulness of repeating microalbumin tests to confirm the diagnosis of microalbuminuria. Repeating this test to reduce the error introduced by diurnal variation in the urine sample, as recommended by the American Diabetes Association, does not necessarily increase the predictive value. Although semiquantitative tests vary in accuracy with the specific gravity of urine (a variation that is substantially corrected for with quantitative tests), the authors note that the practical advantages of semiquantitative tests may outweigh their disadvantages. They call for a trial of different screening methodologies. They also remind us that much of what we do is based on expert opinion and is improved by closer evaluation of the specific recommendations.

The article by Hueston and colleagues⁹ is a sobering reminder of how, even in our training sites, we fail to institute clinical recommendations. In the 2 practices examined in this study, the rate of microalbumin testing was low. This was not because physicians were selectively screening only patients most likely to benefit and skipping those with proteinuria in whom testing may be less beneficial. Patients were not screened regardless of their risk and were often not started on angiotensin-converting enzyme (ACE) inhibitor therapy even with a positive screening result. I would suggest that the power of the study is misleading, since performing a microalbumin test is more likely a physician behavior than a patient characteristic. The likelihood of a patient having a microalbumin screen is probably nested within individual physician behavior and perhaps nested further within the 2 practices studied because of practice resources, laboratory availability, and similar practice patterns among faculty. It is also difficult to generalize how widespread this problem is. Still, it is an important step forward to recognize that clinical recommendations for microalbumin screening are not being followed within 2 residency practices and perhaps many more.

Preventive services

Of course, identifying the problem is only the first step. We must next take responsibility for improving the delivery of high-quality preventive services. Unfortunately this is not likely to be an easy task, such as the proposed consideration of recommending that everyone with diabetes be placed on an ACE inhibitor. There is very little evidence that patients with type 1 or type 2 diabetes who do not have hypertension and do not have microalbuminuria receive any patient-oriented improvement from long-term administration of ACE inhibitors. To suggest that population-based treatment of people with diabetes with ACE inhibitors would be cheaper or easier misses the point that as physicians we provide the best care for individuals and will (almost) never support the potential sacrifice of an individual’s well-being for societal benefits. Although streamlining the information flow of newly established evidence to daily practice will help, improved delivery of care will ultimately occur one physician at a time. I believe that the authors’ statement that “Since physicians do not screen reliably for fatal diseases with screening modalities that have been available for decades, it is unlikely that their behavior is likely to improve,” regrettably overlooks the enormous successes that have occurred in lipid management, cervical cancer, and breast cancer. Translating the latest recommendations into current practice will always be a struggle. But one of the strengths of family physicians is the continuing personal care that we can provide. Family physicians will not abandon the initiation of new preventive services and should not compromise personal care by treating populations at the expense of individuals.

The practice of prevention is always changing. It is a sign of strength that we can identify problems within our practices, and a justification of the confidence of our patients that we can correct those problems. Although expert recommendations flourish, it is essential for primary care physicians to examine all the elements of screening programs to ensure that the evidence demonstrates both effective and efficient care delivery. Diabetes preventive care now also entails close control of hypertension and cholesterol, periodic foot and eye examinations, and microalbumin testing.

Recognizing these new demands, the American Diabetes Association has recently announced the initiation of the Diabetic Cardiovascular Disease Initiative to emphasize the importance of cardiovascular disease prevention, and the American Medical Association, the National Council on Quality Assurance, and the Joint Commission on Health Care Accreditation have announced new performance measures for diabetes care that include a wide variety of important disease prevention practices.¹⁰ Family physicians, perhaps more than any other specialty, are continuing to discover better ways to deliver preventive care effectively and efficiently to our patients with diabetes.

In the United States, 5.9% of the population has diabetes mellitus, and 800,000 people are given a diagnosis of this disease every year.¹ Between 1990 and 1998 the age-adjusted prevalence of diabetes rose by 33%.² It continues to affect younger people; since 1990 the United States experienced a 70% increase in the number of individuals aged between 30 and 39 years who were given the diagnosis of this chronic disease. Diabetes is the single most common cause of end-stage renal disease (ESRD), and ESRD rates continue to increase because of higher prevalence and longer life expectancies for people with type 2 diabetes.

Prevalence

Without interventions, 20% to 40% of type 2 patients with microalbuminuria eventually develop overt nephropathy, and it is estimated that 20% will have ESRD after 20 years.³ The clinical impact is seen in the frequency of treatment for new cases of ESRD from 1984 to 1996. It increased by 44% among persons younger than 45 years with diabetes, by 213% among those 45 to 64 years, by 405% among persons 65 to 74 years, and by 644% among those 75 years and older.⁴ Appropriate treatment can substantially reduce the incidence of nephropathy and the risk of acquiring other diabetes-related complications.^5,6 However, the benefits of effective diabetes treatment will only be fully realized if preventive therapy is effectively integrated into clinical practice. Since the vast majority of patients with diabetes receive their care from a primary care physician, the focal point for the improvement of diabetes care should be the primary care office.⁷

Screening

Two articles in this month’s issue of JFP shed additional light on screening for microalbuminuria among people with diabetes. Scheid and colleagues⁸ systematically review the literature for evidence that screening for microalbuminuria prevents nephropathy in patients with diabetes. It is a short list of articles. The authors found no controlled trials of screening to prevent progression to nephropathy. It has only been in the last several years that good evidence has become available that treating microalbuminuria prevents progression to nephropathy in both type 1 and type 2 diabetes. The authors are asking a 2-part question: (1) How effective is screening for the detection of microalbuminuria? and (2) How effective is the treatment of microalbuminuria in the prevention of nephropathy? Evaluation of the evidence behind screening is incomplete without both answers. Although treatment of microalbuminuria is effective, the mechanics behind screening are complex. The authors raise an interesting challenge regarding the usefulness of repeating microalbumin tests to confirm the diagnosis of microalbuminuria. Repeating this test to reduce the error introduced by diurnal variation in the urine sample, as recommended by the American Diabetes Association, does not necessarily increase the predictive value. Although semiquantitative tests vary in accuracy with the specific gravity of urine (a variation that is substantially corrected for with quantitative tests), the authors note that the practical advantages of semiquantitative tests may outweigh their disadvantages. They call for a trial of different screening methodologies. They also remind us that much of what we do is based on expert opinion and is improved by closer evaluation of the specific recommendations.

The article by Hueston and colleagues⁹ is a sobering reminder of how, even in our training sites, we fail to institute clinical recommendations. In the 2 practices examined in this study, the rate of microalbumin testing was low. This was not because physicians were selectively screening only patients most likely to benefit and skipping those with proteinuria in whom testing may be less beneficial. Patients were not screened regardless of their risk and were often not started on angiotensin-converting enzyme (ACE) inhibitor therapy even with a positive screening result. I would suggest that the power of the study is misleading, since performing a microalbumin test is more likely a physician behavior than a patient characteristic. The likelihood of a patient having a microalbumin screen is probably nested within individual physician behavior and perhaps nested further within the 2 practices studied because of practice resources, laboratory availability, and similar practice patterns among faculty. It is also difficult to generalize how widespread this problem is. Still, it is an important step forward to recognize that clinical recommendations for microalbumin screening are not being followed within 2 residency practices and perhaps many more.

Preventive services

Of course, identifying the problem is only the first step. We must next take responsibility for improving the delivery of high-quality preventive services. Unfortunately this is not likely to be an easy task, such as the proposed consideration of recommending that everyone with diabetes be placed on an ACE inhibitor. There is very little evidence that patients with type 1 or type 2 diabetes who do not have hypertension and do not have microalbuminuria receive any patient-oriented improvement from long-term administration of ACE inhibitors. To suggest that population-based treatment of people with diabetes with ACE inhibitors would be cheaper or easier misses the point that as physicians we provide the best care for individuals and will (almost) never support the potential sacrifice of an individual’s well-being for societal benefits. Although streamlining the information flow of newly established evidence to daily practice will help, improved delivery of care will ultimately occur one physician at a time. I believe that the authors’ statement that “Since physicians do not screen reliably for fatal diseases with screening modalities that have been available for decades, it is unlikely that their behavior is likely to improve,” regrettably overlooks the enormous successes that have occurred in lipid management, cervical cancer, and breast cancer. Translating the latest recommendations into current practice will always be a struggle. But one of the strengths of family physicians is the continuing personal care that we can provide. Family physicians will not abandon the initiation of new preventive services and should not compromise personal care by treating populations at the expense of individuals.

The practice of prevention is always changing. It is a sign of strength that we can identify problems within our practices, and a justification of the confidence of our patients that we can correct those problems. Although expert recommendations flourish, it is essential for primary care physicians to examine all the elements of screening programs to ensure that the evidence demonstrates both effective and efficient care delivery. Diabetes preventive care now also entails close control of hypertension and cholesterol, periodic foot and eye examinations, and microalbumin testing.

Recognizing these new demands, the American Diabetes Association has recently announced the initiation of the Diabetic Cardiovascular Disease Initiative to emphasize the importance of cardiovascular disease prevention, and the American Medical Association, the National Council on Quality Assurance, and the Joint Commission on Health Care Accreditation have announced new performance measures for diabetes care that include a wide variety of important disease prevention practices.¹⁰ Family physicians, perhaps more than any other specialty, are continuing to discover better ways to deliver preventive care effectively and efficiently to our patients with diabetes.

Evidence summary

Several studies demonstrating the accuracy of helical CT have been published recently.^1-3 The most convincing are 2 prospective studies done in emergency departments in Belgium and Australia.^1,2 Both compared helical CT with intravenous pyelography (IVP) and used the gold standard of recovery and direct visualization of a stone. The Australian study enrolled 40 consecutive patients; the Belgian study enrolled 53 of 70 consecutive patients. In these 2 studies, helical CT correctly identified every instance of urinary tract stones. In contrast, IVP failed to detect stones in a third of the patients with stones, and 44% of the negative readings were false-negatives. Both tests did well in reporting negative results for those patients without stones (specificity = 97% for both tests). In terms of likelihood ratios, helical CT and IVP had positive likelihood ratios of 29 and 19, respectively, and negative likelihood ratios of 0 and 0.36 (a lower negative likelihood ratio is better). In other words, helical CT appears to be far superior to IVP in ruling out the presence of urinary tract stones. As an additional comparison, another study found that urine dipstick testing for hematuria yielded positive likelihood ratios of 1.25 and a negative likelihood ratio of 0.55.⁴ The accuracy of ultrasonography appears to fall somewhere in between hematuria testing and IVP.⁵ The Table shows an overall comparison of these diagnostic tests.

In addition to its better accuracy, several studies discuss the better safety profile and decreased diagnostic time of helical CT than IVP.^6-8 The risk of contrast reaction during IVP is between 5% and 10%, with a mortality of approximately 1 in 40,000. Helical CT (when evaluating for stones) does not use contrast, although the radiation exposure is approximately twice that of IVP.⁶ The costs of helical CT and IVP are comparable, and helical CT becomes more cost effective when the shorter time to discharge with a definitive diagnosis is considered.^7,8 Several authors also cite instances when helical CT uncovered a nonurinary cause for patients’ symptoms that IVP would have missed.^8,9

Access to helical CT is improving throughout the United States, and individual radiologists can become quickly skilled at helical CT interpretation.¹⁰ Physicians should confirm that their local radiologists are comfortable with helical CT readings before incorporating this into their diagnostic routines.

Recommendations from others

Several urology and radiology departments have published reviews lately supporting the use of helical CT over other diagnostic testing for urinary tract stones.^9,11 No official recommendations from professional organizations were found.

Evidence summary

Several studies demonstrating the accuracy of helical CT have been published recently.^1-3 The most convincing are 2 prospective studies done in emergency departments in Belgium and Australia.^1,2 Both compared helical CT with intravenous pyelography (IVP) and used the gold standard of recovery and direct visualization of a stone. The Australian study enrolled 40 consecutive patients; the Belgian study enrolled 53 of 70 consecutive patients. In these 2 studies, helical CT correctly identified every instance of urinary tract stones. In contrast, IVP failed to detect stones in a third of the patients with stones, and 44% of the negative readings were false-negatives. Both tests did well in reporting negative results for those patients without stones (specificity = 97% for both tests). In terms of likelihood ratios, helical CT and IVP had positive likelihood ratios of 29 and 19, respectively, and negative likelihood ratios of 0 and 0.36 (a lower negative likelihood ratio is better). In other words, helical CT appears to be far superior to IVP in ruling out the presence of urinary tract stones. As an additional comparison, another study found that urine dipstick testing for hematuria yielded positive likelihood ratios of 1.25 and a negative likelihood ratio of 0.55.⁴ The accuracy of ultrasonography appears to fall somewhere in between hematuria testing and IVP.⁵ The Table shows an overall comparison of these diagnostic tests.

In addition to its better accuracy, several studies discuss the better safety profile and decreased diagnostic time of helical CT than IVP.^6-8 The risk of contrast reaction during IVP is between 5% and 10%, with a mortality of approximately 1 in 40,000. Helical CT (when evaluating for stones) does not use contrast, although the radiation exposure is approximately twice that of IVP.⁶ The costs of helical CT and IVP are comparable, and helical CT becomes more cost effective when the shorter time to discharge with a definitive diagnosis is considered.^7,8 Several authors also cite instances when helical CT uncovered a nonurinary cause for patients’ symptoms that IVP would have missed.^8,9

Access to helical CT is improving throughout the United States, and individual radiologists can become quickly skilled at helical CT interpretation.¹⁰ Physicians should confirm that their local radiologists are comfortable with helical CT readings before incorporating this into their diagnostic routines.

Recommendations from others

Several urology and radiology departments have published reviews lately supporting the use of helical CT over other diagnostic testing for urinary tract stones.^9,11 No official recommendations from professional organizations were found.

Evidence summary

Several studies demonstrating the accuracy of helical CT have been published recently.^1-3 The most convincing are 2 prospective studies done in emergency departments in Belgium and Australia.^1,2 Both compared helical CT with intravenous pyelography (IVP) and used the gold standard of recovery and direct visualization of a stone. The Australian study enrolled 40 consecutive patients; the Belgian study enrolled 53 of 70 consecutive patients. In these 2 studies, helical CT correctly identified every instance of urinary tract stones. In contrast, IVP failed to detect stones in a third of the patients with stones, and 44% of the negative readings were false-negatives. Both tests did well in reporting negative results for those patients without stones (specificity = 97% for both tests). In terms of likelihood ratios, helical CT and IVP had positive likelihood ratios of 29 and 19, respectively, and negative likelihood ratios of 0 and 0.36 (a lower negative likelihood ratio is better). In other words, helical CT appears to be far superior to IVP in ruling out the presence of urinary tract stones. As an additional comparison, another study found that urine dipstick testing for hematuria yielded positive likelihood ratios of 1.25 and a negative likelihood ratio of 0.55.⁴ The accuracy of ultrasonography appears to fall somewhere in between hematuria testing and IVP.⁵ The Table shows an overall comparison of these diagnostic tests.

In addition to its better accuracy, several studies discuss the better safety profile and decreased diagnostic time of helical CT than IVP.^6-8 The risk of contrast reaction during IVP is between 5% and 10%, with a mortality of approximately 1 in 40,000. Helical CT (when evaluating for stones) does not use contrast, although the radiation exposure is approximately twice that of IVP.⁶ The costs of helical CT and IVP are comparable, and helical CT becomes more cost effective when the shorter time to discharge with a definitive diagnosis is considered.^7,8 Several authors also cite instances when helical CT uncovered a nonurinary cause for patients’ symptoms that IVP would have missed.^8,9

Access to helical CT is improving throughout the United States, and individual radiologists can become quickly skilled at helical CT interpretation.¹⁰ Physicians should confirm that their local radiologists are comfortable with helical CT readings before incorporating this into their diagnostic routines.

Recommendations from others

Several urology and radiology departments have published reviews lately supporting the use of helical CT over other diagnostic testing for urinary tract stones.^9,11 No official recommendations from professional organizations were found.