Inter-relation between diabetes mellitus and hypertension in terms of incidence and prediction in Saudi Arabia: a retrospective cohort study

Abstract Background Hypertension (HTN) and type 2 diabetes mellitus (T2DM) are interconnected metabolic disorders with escalating global incidence and prevalence. However, no longitudinal studies have specifically examined the incidence of HTN and T2DM in the same study population. This study aimed to elucidate the association between HTN and T2DM and ascertain their respective roles in the development of each other. Methods This retrospective cohort study encompassed 809 Saudi patients from primary healthcare centers in Al Madinah Al Munawarah, Saudi Arabia. The sample was stratified into three cohorts: 226 patients with HTN but without T2DM, 274 patients with T2DM but without HTN, and 309 patients devoid of both T2DM and HTN. Over a retrospective follow-up period of approximately 5 years, incidence density rates (IDR) were computed for HTN in the T2DM cohort, T2DM in the HTN cohort, and both HTN and T2DM in the control cohort. Multiple logistic regression analysis was employed to identify predictors of HTN and T2DM. Results The IDR of T2DM among patients with HTN stood at 73.9 (95% confidence interval CI 56, 92) per 1000 person-years, in contrast to 33.9 (95% CI 24, 44) per 1000 person-years in the control cohort (adjusted odds ratio OR = 7.1, 95%CI 3.55, 14.13). Conversely, the IDR of HTN among patients with type-2 T2DM was 55.9 (95% CI 42, 70) per 1000 person-years, while in the control cohort, it was 20.8 (95% CI 13, 28) per 1000 person-years (adjusted OR = 5.8, 95% CI 3.11, 11.09). Significant predictors of HTN in the logistic regression model encompassed age, smoking status, family history of HTN, T2DM status, and body mass index (BMI). Similarly, significant predictors of T2DM in the logistic regression model included age, sex, family history of T2DM, HTN, and BMI. Conclusion This study unveils HTN and T2DM as mutually significant risk factors. The IDR of each condition in the presence of the other significantly exceeded that among individuals devoid of HTN or T2DM.