Association between inflammation and sleep apnea in the MACS cohort

Prompted by the concern that systemic inflammation may contribute to sleep apnea, Susheel Patil and colleagues from Johns Hopkins University presented an interesting analysis from the gently named SIESTA study (Study of Immune Effects on Sleep, (HIV) Treatment and Apnea).

The study looked at obstructive sleep apnea (OSA) and the relationship with inflammation markers (TNF-alpha soluble TNF-a receptors I and II and IL-6), in three groups of men from the MACS cohort: HIV-positive and not on HAART (n=41), HIV-positive and on HAART (n=58) and HIV negative (n=60). Severity of OSI was defined by the number of events per hour detected during a nocturnal sleep study: 5-15 = mild, 15-30 = moderate, and >30 = severe. Obesity is the strongest predictor of OSI, but OSI is also independently associated with hypertension, cardiovascular disease, stroke, diabetes mellitus and reduced quality of life.

OSI >15 was higher in the HIV- negative group (57%) compared to the HAART (41%) and no-HAART (44%) groups. However, the HIV-negative group had a significantly greater mean BMI (28.6 +7.2kg/m2) and waist circumference (98.6 +16.9cms) compared to the HAART (25.5 +4.5kg/m2 and 93.8 +11.5cm) and no-HAART (25.4 +4.1 kg/m2 and 91.8 +12.8) HIV-positive groups and a trend to greater trunk weight.

When looking at participants with normal BMI (<25 kg/m2) however, the relationship indicated a trend for higher prevalence in the no-HAART group: 25% HIV-negative (n=20), 24% on HAART (n=29) and 50% in the no HAART group (n=22); (p=0.1).

Median levels of all four inflammatory markers were higher in the HIV-positive men compared to the HIV-negative men, and were higher in the no-HAART group compared to the HAART group. Within the no-HAART group, men with moderate severe OSA had higher levels of TNF-a and IL-6 compared to men with no or less severe OSI, although this difference was not observed between men in the other groups.

The study concluded that rates of OSI were high in HIV-positive men, even when BMI was normal, and that more severe symptoms was associated with systemic inflammation suggesting a different aetiology compared to men who are HIV-negative.

Ref: Patil SP et al. Association between systemic inflammation and obstructive sleep apnea in men with or at risk for HIV infection from the Multicenter AIDS Cohort Study (MACS). 11th Intl Workshop on Adverse Drug Reactions. 26-28 October 2009, Philadelphia. Oral abstract O-25. Antiviral therapy 2009; 14 Suppl 2: A19.