[Obstructif sleep apnea-hypopnea syndrome: evolution of an old concept]

Obstructive sleep apnea is an important predictor of hepatic fibrosis in patients with nonalcoholic fatty liver disease in a tertiary care center

BACKGROUND

The association of obstructive sleep apnea (OSA) with nonalcoholic fatty liver disease (NAFLD) has only been studied in selected subgroups such as the morbidly obese. We aimed to determine the prevalence and effect of OSA on NAFLD and vice versa in unselected patients attending the outpatient department.

METHODS

OSA was diagnosed by polysomnography, done in patients having symptoms of OSA, in patients with NAFLD attending the liver clinic. Polysomnography-proven patients with OSA attending the chest clinic were evaluated for NAFLD by ultrasonography. Anthropometry, liver function tests, metabolic syndrome evaluation and transient elastography were performed in all patients.

RESULTS

Three (3%; 95% CI 1.03-8.45%) out of 100 patients with NAFLD (mean age 41 ± 11 years) had symptomatic OSA. Of 23 patients with OSA (mean age 46 ± 12 years,), 3 (13%) had mild, 5 (22%) moderate and 15 (65%) severe OSA. Twenty-one (91.3%; 95% CI 73.2-97.6%) patients with OSA had NAFLD, while raised hepatic transaminase levels were seen in seven (30.4%; 95% CI 15.6-50.9%). Body mass index (OR 1.21, 95% CI 1.02-1.44) and male gender (OR 4.79, 95% CI 1.12-20.48) were significant independent predictors of OSA in NAFLD. The apnea-hypopnea index (OR 1.084, 95% CI 1.002-1.172), a marker of OSA severity, was the only significant independent predictor of significant fibrosis in patients with NAFLD.

CONCLUSIONS

Prevalence of symptomatic OSA in patients with NAFLD is low and is predicted by male gender and obesity. Prevalence of NAFLD in patients with OSA is very high. Significant hepatic fibrosis in patients with NAFLD is predicted by OSA independent of obesity and metabolic syndrome.

Prevalence of metabolic syndrome in a north Indian hospital-based population with obstructive sleep apnoea

BACKGROUND & OBJECTIVES

Obstructive sleep apnoea (OSA) is known to be associated with cardiovascular risk factors and metabolic syndrome (MS). The burden of MS in patients with OSA in India is unknown. We investigated the prevalence of MS and its components in a cross-sectional study in patients with and without OSA in a hospital-based population of a tertiary health care centre in New Delhi, India.

METHODS

Consecutive patients undergoing overnight polysomnography in the Sleep Laboratory of the Department of Internal Medicine of All India Institute of Medical Sciences (AIIMS) hospital, New Delhi, were studied. Anthropometry and body composition analysis, blood pressure (BP), fasting blood glucose, insulin resistance by homeostasis model assessment (HOMA-IR) and fasting blood lipid profile were measured. MS was defined using the National Cholesterol Education Program Adult treatment panel III criteria, with Asian cut-off values for abdominal obesity.

RESULTS

Of the 272 subjects recruited, 187 (82%) had OSA [apnoea-hypopnoea index (AHI)>5 events/h] while 40 (18%) had a normal sleep study. Prevalence of MS in OSA patients was 79 per cent compared to 48 per cent in non-OSA individuals [OR 4.15, (2.05-8.56), P<0.001]. Prevalence of OSA in mild, moderate and severe OSA was 66, 72 and 86 per cent, respectively (P<0.001). Patients with OSA were more likely to have higher BP [OR: 1.06 (1.02-1.11)], fasting insulin [OR: 1.18 (1.05-1.32)], HOMA-IR [OR: 1.61 (1.11-2.33)] and waist circumference [OR: 1.20 (1.13-1.27)].

INTERPRETATION & CONCLUSIONS

Our findings suggest that OSA is associated with a 4-fold higher occurrence of MS than patients without OSA. The prevalence of MS increases with increasing severity of OSA, therefore, early detection will be beneficial.