P5725Association between comorbidity and prescription of anti-hypertensives in incident hypertension: a population cohort study

Abstract

Background: Hypertensive patients often have comorbidities and it is not clear whether these affect prescription of antihypertensive drugs. To our knowledge, there are no longitudinal studies that have investigated antihypertensive prescription in people with incident diagnosis of hypertension, by presence or absence of a large number of cardiovascular and non-cardiovascular comorbidities. Purpose(s): In patients with incident hypertension, we investigated the association between number of prescribed antihypertensive classes and comorbidities and examined this association over time. Method(s): We used a random 10% sample of the UK Clinical Practice Research Datalink and identified patients diagnosed with incident hypertension in primary care between 2000 and 2014. We classified antihypertensives into angiotensin-converting-enzyme (ACE)-inhibitors and angiotensin-receptor blockers, beta-blockers, calcium-channel-blockers, diuretics and other, and examined 22 comorbidities, classified into six categories: cardiometabolic, respiratory, mental illness, musculoskeletal, cancer or other. We used Poisson regression at annual timepoints up to 10 years after diagnosis of hypertension, to estimate the rate ratio (RR), and 95% confidence interval (CI), of number of antihypertensive classes prescribed. The exposure was number of comorbidities, specific comorbidity and disease category. We adjusted for age, sex, socioeconomic status, ethnicity, cumulative blood pressure, year of hypertension diagnosis, cholesterol, body mass index and smoking status. Result(s): We identified 32,484 patients with incident hypertension. The most prevalent conditions at diagnosis were arthritis (26.5%), depression (16.3%) and hyperlipidaemia (13.7%). Patients with more comorbidities were generally more likely to be prescribed more classes of antihypertensives, and this relationship was preserved over time after diagnosis of hypertension. One year after diagnosis of hypertension, patients with 5 or more conditions were 13% more likely to be prescribed an additional antihypertensive class compared to those with no conditions (RR 1.13 [CI 1.09-1.18]). Additionally, patients with cardiometabolic conditions were more likely to be prescribed an additional antihypertensive class, and this remained stable over time (1 year: 1.07 [1.05-1.08], 10 years:1.08 [1.05- 1.12]), but dementia patients were significantly less likely to be prescribed an additional antihypertensive class from 2 years after diagnosis (RR 0.87 [0.76-0.99]). Conclusion(s): Patients with comorbidities are generally more likely to receive antihypertensives compared to those without regardless of time after hypertension diagnosis. This is consistent across most groups of comorbidities but tends to be more pronounced for cardiometabolic comorbidities and reversed for some conditions such as dementia. An increased awareness of the impact of comorbidities on antihypertensive prescribing may improve hypertension management in primary care.