| HOME | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|---|
| ||||||||||||||||||||||
EDITORIAL |
Department of Medicine, University of British Columbia, and Department of Medicine, Vancouver Hospital, Canada.
Address correspondence to Graydon S. Meneilly, MD, Department of Medicine, University of British Columbia, Head, Department of Medicine, Vancouver Hospital, Room 3300, 950 West 10th Ave., Vancouver, British Columbia, V5Z 4E3 Canada. E-mail: meneilly{at}interchange.ubc.ca
DIABETES is common in elderly persons. By the age of 75, approximately 25% of the U.S. population will be afflicted with this illness (1). Because of its associated complications, diabetes in the aged has a significant impact on quality of life (2). Therefore, further investigation is timely. Three articles in this issue of the Journal address important aspects of this burgeoning health issue.
In the first article, Corsonello and colleagues (3) highlight the prevalence of concealed renal failure in elderly patients with diabetes and emphasize the associated increased risk for adverse drug reactions. Adverse drug reactions are the commonest iatrogenic complication in elderly medical inpatients (4,5). The recently published Canadian Adverse Events Study (5) demonstrated that the most common adverse drug reactions in elderly persons are renal toxicity and inappropriate dosing of medications based on a lack of understanding of impairments in underlying renal function. It has been known for many years that renal function declines with age and that serum creatinine is a relatively poor marker of renal function because of decreases in muscle mass (6). Corsonello and colleagues used a nomogram to calculate glomerular filtration rate (GFR), and demonstrated that concealed renal dysfunction is present in nearly 20% of older patients with diabetes. These patients had a substantially increased risk of adverse drug reactions. This study suggests that, if we are to substantially reduce the risk of iatrogenic events in hospital, we should focus on elderly patients with diabetes. Our efforts should be particularly directed to patients who are taking larger numbers of medications because these are the patients most at risk.
Several caveats should be noted in regard to the article by Corsonello and colleagues. First, it is likely that the authors underestimated the incidence of diabetes because the condition was diagnosed based on International Classification of Diseases 9th revision (ICD-9) codes, and it is certain that a substantial number of cases were missed. As the authors note, the method used to calculate GFR indicated a higher incidence of concealed renal function than did other commonly used formulas, such as that of Cockcroft and Gault (7). Clinicians should be familiar with the method used to calculate GFR in their local laboratory to properly assimilate the results of this study into their practice. Finally, the ascertainment of adverse drug reactions may have been imperfect (because it was based on the attending physician's judgment), and it is probable that a substantial number of adverse drug reactions were missed. Nonetheless, Corsonello and colleagues should be commended for an important contribution to the literature.
In another article in this issue, Al Snih and colleagues report on the association between diabetes and lower body disability in older Mexican Americans (8). Previous studies have demonstrated that diabetes is one of the strongest predictors of functional decline in older Americans (9–12). The current study confirms this finding in an important ethnic group. After 7 years of follow-up, 50% of elderly diabetics developed significant limitations in lower body function. This study demonstrates the major impact of diabetes on quality of life in elderly persons. There are several factors that could contribute to lower extremity dysfunction in this patient population. Macrovascular and microvascular disease, foot problems, peripheral neuropathy, and arthritis are all more common in elderly patients with diabetes (2) and would be expected to contribute to lower extremity disability. Indeed, the authors demonstrate that evidence of vascular disease was more common in patients with disability. Of interest, obesity and depression were also associated with functional impairment in these patients. Readers should be aware that this study had several limitations, most notably that the diagnosis of diabetes and its complications was based on self-report, so it is likely that a substantial number of cases and complications were missed.
In a related article, Maurer and colleagues (13) found that, when compared to patients without diabetes, elderly nursing home patients with diabetes had impaired balance and an increased risk of falling. Once again, a potential confound of this study is that diabetes was underdiagnosed, because the determination was based on chart review. In addition, the sample size was small. There were a number of associations between falls and other medical conditions which did not reach statistical significance, presumably as a result of the sample size. The authors speculate that many of the factors which contribute to lower extremity disability are likely to increase the risk of falls in this patient population. Of interest, they note that, whereas polypharmacy was associated with an increased risk of falls, antidepressant use appeared to be protective. Although the latter finding would seem to be in contradistinction to previous reports (14–16), the authors point out that patients with depression were more likely to be immobile, which may partially explain their reduced risk of falls.
If diabetes is associated with lower extremity dysfunction and falls in elderly persons, is there anything that can be done to prevent this from occurring? Although there are no data from randomized controlled trials, such as the U.K. Prospective Diabetes Study (UKPDS) or the Diabetes Control and Complications Trial (DCCT) (17,18), to indicate that optimizing glycemic control improves outcome in elderly persons, several prospective epidemiologic studies have indicated that better glycemic control reduces the risk of development or progression of macrovascular or microvascular complications, neuropathy, and foot problems in this patient population (2). In addition, randomized controlled trials demonstrate that treatment of hyperlipidemia and hypertension will reduce micro- and macrovascular complications in elderly diabetic persons (19–21). Presumably, a reduced rate of complications would reduce the likelihood of lower extremity disability and, by extension, the risk of falls. Finally, resistance training has been shown to improve lower extremity function and glycemic control in the elderly patient with diabetes (22), and would seem to be a particularly attractive intervention in this regard.
Summary
The epidemic of diabetes in elderly persons will clearly have a significant impact on the health care system in the 21st century. Carefully conducted investigations such as those reported in this issue of the Journal are essential if we are to deal with this critically important health issue.
F
Decision Editor: John E. Morley, MB, BCh
Received August 16, 2004
Accepted August 16, 2004
References
| ||||||||||||||||||||||
| HOME | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|---|
