Further investigation of the negative association between hypertension and peripheral neuropathy in the elderly: An Oklahoma Physicians Resource/Research Network (OKPRN) study

Background: In a previous cross-sectional study of age-associated peripheral neuropathy (AAPN), we found that a history of hypertension was protective. The purpose of this study, conducted in the same cohort, was to investigate further this association in the same subjects and in a comparison group of older subjects with diabetes mellitus. Methods: Baseline data from 584 subjects involved in a longitudinal study of primary care patients 65 years of age and older, with no history of 10 medical conditions known to cause peripheral neuropathy, were analyzed for associations between peripheral neuropathy by examination and history of hypertension, number of antihypertensive medications, systolic blood pressure, diastolic blood pressure, pulse pressure, and orthostatic hypotension. In addition, we examined associations between neuropathy at baseline and use of specific classes of antihypertensive medications and non-steroidal anti-inflammatory agents ( NSAIDs) in year 3. The analyses were repeated in 110 subjects with diabetes mellitus. Results: History of hypertension, but not the other hypertension-related variables, was negatively associated ( OR, 0.60; 95% CI: 0.40 to 0.90) with AAPN after controlling for age and body mass index (BMI). In 287 subjects evaluated in the 3rd year of the study, beta-blocking agents ( OR, 3.56; 95% CI: 1.58 to 8.03) and NSAIDs ( OR, 2.65; 95% CI: 1.37 to 5.10) were positively associated with AAPN. In subjects with diabetes mellitus, a history of hypertension was again protective, but current pulse pressure ( OR, 1.03; 95% CI: 1.00 to 1.05) was a positive predictor of peripheral neuropathy. There were interesting interactions between pulse pressure and military service and pulse pressure and BMI in diabetic patients. Conclusions: The negative association between hypertension and AAPN remains unexplained. The positive association between pulse pressure and neuropathy in diabetic subjects supports findings from previous studies and suggests that AAPN and the neuropathy of diabetes may be distinct entities. The incidental finding of an association between NSAIDs and AAPN is concerning and should be investigated further.