(P-033) Any Link Between Polypharmacy and the Risk of Mortality Among Patients with Chronic Heart Failure Newly Diagnosed? A Nested Case-control Study

Background: Heart failure (HF) is associated with substantial morbidity, high rates of hospital readmission and polypharmacy. However, the risk of mortality in patients with HF exposed to polypharmacy is poorly studied.

Objectives: To examine the effects of cardiovascular and non-cardiovascular polypharmacy on mortality in patients newly admitted in a hospital with HF as a primary diagnosis.

Methods: We used a patient cohort of incident HF cases, in which we identified patients who were hospitalized with HF as a primary diagnosis and discharged in the community from 1998 to 2015 using ICD-9 and ICD-10 diagnostic codes. Linked Quebec administrative healthcare databases were analyzed to estimate the mortality rate in the year following hospital discharge. Polypharmacy, cardiovascular polypharmacy and non-cardiovascular polypharmacy were respectively defined as exposure to at least 10 drugs of any kind, at least 5 cardiovascular drugs and at least 6 non-cardiovascular drugs in the 3 months prior to the case or the date of control selection. We then conducted a nested-case control study to estimate odds ratios (OR) of all-cause mortality using a multivariate conditional logistic regression. Cases and controls were matched for age at baseline, sex, and follow-up period.

Results: We identified 12,242 HF patients with a mean age of 81.6 years, for which cardiopathy (57.2%), hypertension (55.0%), cardiac arrhythmia (44.5%), and chronic renal failure (41.7%) were the most prevalent comorbidities. The crude incidence rate of mortality during follow-up was 14.2 cases per 100 patients-years in the full cohort. Cardiovascular polypharmacy was related to a lower mortality risk (aOR 0.68 95% CI 0.57-0.80), while polypharmacy of all drugs (aOR 0.91 95% CI 0.73-1.12) and non-cardiovascular polypharmacy (aOR 0.97 95% CI 0.80-1.18) showed no association. Multimorbidity frailty (index≥16 vs <4), hydralazine and spironolactone were related to a 45%, 43% and 27% increased risk of mortality, respectively. However, exposure to angiotensin II inhibitors and beta-blockers were related to a 39% and 23% reduced risk of mortality, respectively.

Conclusions: Our findings suggest that non-cardiovascular polypharmacy was related to a greater tendency of mortality risk; and cardiovascular polypharmacy was related to a lower mortality risk. Sensitivity analyses pertaining to medication changes before death are ongoing.