Relationship between outpatient visit frequency and hypertension control: a 9-year occupational cohort study

The purpose of this study was to investigate the relationship between the frequency of outpatient visits and hypertension control as determined from health insurance records. This 9-year cohort study in Japan was based on 518 participants with hypertension who underwent health checkups in 2004. Participants were aged 35-56 years and none had a history of cardiovascular or cerebrovascular disease. All were covered by the same employee health insurer. Mean annual outpatient visit days at a hospital/clinic during the 9-year period were classified within four quartiles (Q1, Q2, Q3, Q4). Uncontrolled hypertension was defined as a systolic blood pressure (BP) ⩾140 mm Hg and a diastolic BP ⩾90 mm Hg. Logistic regression analysis was used to estimate the multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the prevalence of uncontrolled hypertension in groups Q1, Q2 and Q3 vs. Q4. The median (25th-75th percentile) annual outpatient visit days was 9.4 (4.0-15.5). Uncontrolled hypertension was observed in 62.4% of the participants in 2013. The multivariable-adjusted ORs and 95% CIs for uncontrolled hypertension in Q1, Q2 and Q3 vs. Q4 were 4.03 (2.28-7.12), 1.67 (0.99-2.81) and 1.44 (0.86-2.41), respectively. Uncontrolled hypertension increased significantly as the number of outpatient visits decreased (P for trend <0.001). This tendency was maintained when participants taking antihypertensive agents at baseline were excluded. Our study showed an inverse relationship between outpatient visit frequency and uncontrolled hypertension.