Predictors of medication use, compliance and symptoms of hypotension in a community-based sample of elderly men and women.

Objective: To investigate use of prescription and non-prescription drugs, predictors of drug use and symptoms of postprandial and postural hypotension were examined in 765 men and 846 women.

Method: A questionnaire mailed to 6324 subjects randomly chosen from the electoral roll.

Results: Drug use, both prescription and non-prescription, was greater (P < 0.0001) in women (mean 4.1 total drugs, CI 3.9, 4.3) than in men (3.5 drugs, CI 3.3, 3.7); 41% of women and 36% of men used at least four drugs. Total drugs used were significantly greater in women (standardized regression coefficient (b) = 0.101, P < 0.0001), and increased with the number of diagnoses (b = 0.461, P < 0.0001) and taking antidepressants (b = 0.160, P < 0.0001). Use of non-prescription drugs was also greater in women (b = 0.094, P < 0.0001) and in association with arthritis (b = 0.053, P = 0.036) but decreased with age (b = -0.013, P < 0.0001). Potentially important drug interactions occurred in 10% of subjects and included hypoglycaemic agents with b-blockers and asthma with b-blockers. Symptoms of postprandial hypotension, reported in 2.6% of subjects, increased with the number of drugs used (OR 1.17, CI 1.05, 1.31) and with diabetes (OR 2.27, CI 1.05, 4.89). Symptomatic postural hypotension, recorded by 13% of subjects, related significantly to age (OR 1.04, CI 1.02, 1.06), tranquillisers (OR 1.98, CI 1.11, 3.54), antidepressants (OR 2.23, CI 1.30, 3.84) and ACE inhibitors (OR 2.14, CI 1.42, 3.22).

Conclusion: Reduction in the number and frequency of drug doses and better knowledge about drugs may improve compliance. Observed associations with polypharmacy or hypotension suggest possible approaches to decreasing drug-related illness and limiting the adverse effects of hypotension in the elderly.