High risk of obstructive sleep apnea among hypertensive patients in two tertiary centers in Nigeria

Abstract

Objectives: The prevalence of obstructive sleep apnea (OSA) is rising globally with its associated morbidity and mortality. Although OSA is associated with hypertension and is the leading cause of secondary and resistant hypertension, its presence is usually not actively sought during clinical evaluation of hypertensive patients resulting in a missed opportunity to treat the condition. This study assessed the prevalence of high risk of OSA and excessive daytime sleepiness (EDS) among hypertensive patients. It also assessed the pattern of symptoms of OSA among the participants. Materials and Methods: We used a structured questionnaire to collect data from hypertensive patients aged 18 years and above, who were attending the outpatient clinics of two tertiary hospitals in Enugu state. Data collected include frequency of symptoms of OSA, Epworth sleepiness scale (ESS) score, snoring, tiredness, observed apnea or choking, blood pressure, body mass index, age, neck circumference, and gender (STOPBANG) score, number of comorbidities present, and demography of participants. STOPBANG score of 5–8 classified participants as having high risk of OSA, and ESS >10 as having excessive daytime sleepiness (EDS.). Results: Three hundred and twenty hypertensive patients were recruited (mean age: 56.0 ± 9.5 years; female: 58.8%). The prevalence of high-risk OSA was 13.8% and that of EDS was 6.3%. Snoring, nocturia, tiredness, and observed apnea were significantly present in 90.9%, 90.9%, 81.8%, and 22.7% of those with high risk of OSA (n = 44), respectively, compared with intermediate (60.6%, 91.5%, 53.2%, and 1.6%) and low risk (12.5%, 77.3%, 19.3%, and 1.1%) groups (P < 0.001, P = 0.003, P < 0.001, and P < 0.001, respectively). Gasping, (χ2 [2] = 8.4, P = 0.015); memory loss, (χ2 [2] = 6, P = 0.04); and sleep fragmentation, (χ2 [2] = 9.9, P = 0.007) also showed significant difference between high-, intermediate-, and low-risk OSA groups. Conclusion: The prevalence of the high risk of OSA among hypertensive patients presenting to our tertiary hospitals are modest. Snoring and nocturia are their most common symptoms. We recommend screening hypertensive patients for OSA to identify those at high risk, as they will likely benefit from sleep study and treatment if confirmed.