Prevalence and determinants of masked hypertension among patients with type 2 diabetes mellitus.

There had been no previous study that evaluated the prevalence of masked hypertension (MH), its determinants, and ambulatory blood pressure patterns among patients with type 2 diabetes mellitus (DM) in Nigeria. Among 222 individuals living with type 2 DM with normal clinic blood pressure (SBP < 140 mm Hg and DBP < 90 mm Hg), we obtained 24 h ambulatory blood pressure measurements. Patients were either untreated (77) or treated (145) with antihypertensive medications. The prevalence of MH among the normotensive (untreated) and hypertensive subgroups (treated) was 32.5 and 60% respectively. The prevalence of nocturnal hypertension among all patients was 71.6%, and was significantly higher among patients with masked phenomenon (98.2 vs 46.2%, p < 0.0001) compared to true normotension. The determinants of MH were 5 years or more duration of type 2 DM (odds ratio 2.71, 95% CI 1.21-6.27) and increasing clinic SBP (odds ratio 2.19, 95% CI 1.51-3.36). Masked hypertension is common among patients with type 2 DM. Higher clinic SBP and 5 years or more duration of type 2 DM are the risk factors.