Sleep Apnea in Hypertensive Patients: Relationship with Duration of Hypertension and the Effect of Age

Background: Hypertension is identified as the third leading risk factor for morbidity and as the leading risk factor for mortality worldwide which is estimated to result in 7.5 million deaths annually. Sleep apnea is a breathing disorder characterized by brief interruptions of breathing during sleep. Even though literature consistently relates presence of sleep apnea with hypertension, there is a dearth of data evaluating the relationship between duration of hypertension and presence of sleep apnea, both locally and internationally. Objectives: 1)To study the relationship between duration of hypertension and sleep apnea in hypertensive patients and 2) To assess the effect of age on such a relationship. Materials and Methods: A cross-sectional study was carried outon a total of 300 conveniently sampled patients, aged 18 or above, from the medical outpatient department of a secondary care hospital of Karachi after taking ethical approval. The inclusion criteria were self-reported history of hypertension and being on anti-hypertensive medication. Age, duration of hypertension and presence of sleep apnea in each patient were evaluated with the help of a structured questionnaire developed specifically for the study. The data were analyzed on SPSS version 20. Qualitative data were expressed as frequency and percentages. Chi-square-test was used for inferential analysis. The significance level was set at 0.05. Results: The study results revealed a significant positive association between longer duration of hypertension and presence of sleep apnea (p=0.02) where patients with longer duration of hypertension had higher prevalence of sleep apnea than those with shorter duration (42.1% vs. 29.0%) though after controlling for the confounding effects of age through stratification this association no longer persisted. Conclusion: The study results revealed a positive association between longer duration of hypertension and presence of sleep apnea, albeit only before controlling for the potential confounding effects of age. Nevertheless, further evaluation of this intriguing relationship is recommended. Key words: Sleep apnea, hypertensive patients, duration of hypertension, age. Study was carried out on a total of 300 conveniently sampled patients, aged 18 or above, from the medical outpatien