Diabetes Linked to Irritative Lower Urinary Tract Symptoms, Nocturia

Diabetes is positively associated with irritative lower urinary tract symptoms (LUTS) and nocturia but not benign prostatic hyperplasia (BPH), according to the results of a multiethnic, community-based study.

"Typically, clinicians treat BPH and type 2 diabetes as separate entities, although some have suggested that diabetes may be a risk factor for the development and progression of BPH," write Aruna V. Sarma, PhD, from the University of Michigan in Ann Arbor, and colleagues. "Clinical uncertainty stems from the fact that both diabetic neuropathy and BPH can lead to dysfunctional bladder storage and emptying, which makes it difficult to determine the extent to which diabetes and/or BPH contributes to voiding dysfunction in these patients. To more clearly understand the association between diabetes and BPH it is important to examine the full spectrum of clinical markers of BPH including lower urinary tract symptoms (LUTS), urinary flow, prostatic volume, and serum prostate-specific antigen (PSA) concentrations."

The objective of this study was to evaluate associations between diabetes and clinical markers of BPH in community-dwelling white and black men aged 40 to 79 years.

The investigators combined data from the Olmsted County Study of Urinary Symptoms and Health Status and the Flint Men’s Health Study (total study sample, 2484 men). Severity of LUTS, peak urinary flow rates, prostate volume, and serum PSA levels were compared in men with and without self-reported, clinician-diagnosed diabetes.

Diabetes, which was reported by 170 (6.8%) men, was positively associated with increased irritative LUTS and specifically nocturia. These patterns were consistent across racial groups and were still present after adjustment for age, body mass index (BMI), and socioeconomic status indicators. The relationship between irritative LUTS and diabetes was greater in black men. There were no apparent associations between diabetes and prostate volume, PSA level, and peak urinary flow rate.

The multiethnic community-based study demonstrates positive associations between diabetes and irritative LUTS and nocturia, the study authors write. "Moreover, the association between irritative LUTS and diabetes is increased in black men. There was no strong evidence for an association between diabetes and BPH across measures more specific to BPH (i.e., prostate volume, PSA, and peak urinary flow rate)."

"Taken together, our findings suggest that the presence of diabetes may be less related to prostate growth and more related to the dynamic components of lower urinary tract function," the study authors conclude. "Further evaluations of the association between diabetes and BPH and related racial variations are warranted."

Practice Pearls

• Type 2 diabetes is associated with an increased incidence of irritative LUTS and nocturia.
• Type 2 diabetes is not associated with an increased association with obstructive bladder symptoms or BPH, measures of PSA levels, and prostate volume.

Diabetes Care. March 2008;31:476-482.