ObjectiveWhile studies evaluating the prevalence of depression and hypertension have been extensively carried out in high income countries, there is a paucity of information assessing the prevalence of depression within hypertensive patients in low income nations. The primary objective of this study was to investigate the prevalence of undiagnosed depression in hypertensive patients within a tertiary care facility in Karachi, Pakistan. The secondary objective was to assess factors associated with undiagnosed depression in this group.MethodsA cross-sectional study was conducted at the Civil Hospital Karachi Outpatient Department from January 2017 to April 2017. The sample population was composed of 411 hypertensive patients. Interviews were conducted after taking informed consent, with data concerning basic demographic details and lifestyle habits gathered. Blood pressure was recorded and its severity was classified as per the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7) guidelines. Depression was evaluated and its severity classified as per the Patient Health Questionnaire-9 (PHQ-9) scale, with a score of 10 or above set as the cut-off point. Data were entered and analyzed using the IBM Statistical Package for the Social Sciences 23.0. (IBM, NY, USA)ResultsThe prevalence of depression within 411 hypertensive patients was 40.1% (n = 165). The mean age of the sample was 45.7 ± 11.2 years, and the majority were females (72%, n = 295), unemployed (72%, n = 296), had primary or no education (67%, n = 277), and were of low socioeconomic status (78%, n = 321). The average systolic and diastolic blood pressures were 143.8 ± 21.7 and 93.3 ± 15.5 mm Hg, respectively. Factors which had a significant association with depression were gender (p = 0.009), age class (p = 0.035), educational status (p = 0.000), employment status (p = 0.003), socioeconomic status (p = 0.008), physical activity (p = 0.025), smoking (p = 0.017), and family history of hypertension (p = 0.022).ConclusionWith such a high prevalence rate of undiagnosed depression within hypertensive patients, it is pertinent to establish screening programs for early detection and community programs to raise awareness regarding long-term complications of untreated depression.