With psoriasis and obstructive sleep apnea (OSA) sharing various comorbidities and having a common pathogenesis of inflammatory and immune imbalance, many studies have examined the association between the two conditions. However, the results of these studies have differed. In order to evaluate the evidence on the bidirectional association of psoriasis and OSA, Ching-Chi Chi, MD, MMS, DPhil, Tzong-Yun Ger, MD, and Yun Fu, MD, conducted a systematic review and meta-analysis of case-control, cross-sectional, and cohort studies in the MEDLINE and Embase databases.

Exploring the Data

The researchers used the Newcastle-Ottawa Scale to evaluate the risk of bias of included studies and performed random-effects model meta-analysis to calculate pooled odds ratio (ORs) with 95% confidence intervals (CIs) for case-control and cross-sectional studies as well as pooled incidence rate ratio (IRR) with 95% CIs for cohort studies in association between psoriasis and OSA. Four case-control or cross-sectional studies and three cohort studies with a total of 5.8 million subjects were included.

Increased risk of OSA among patients with psoriasis was found in one cohort study, one cross-sectional study, and two case-control studies. Meta-analysis of the latter three showed a significant association of psoriasis with OSA among nearly 300,000 study subjects, with a pooled OR of 2.60, “indicated that patients with psoriasis are 2.6-fold more likely to develop OSA when compared with patients without psoriasis,” adds Dr. Ger (Figure 1). “Although these three studies had considerable statistical heterogeneity, all had consistently positive results.” In the cohort study, patients with mild psoriasis had a consistently increased risk of OSA (adjusted IRR, 1.36), as did those with severe psoriasis (adjusted IRR, 1.53) and psoriatic arthritis (adjusted IRR, 1.98).

Conversely, a consistent increase in psoriasis among patients with OSA was found across three cohort studies and one case-control study. A meta-analysis of the cohort studies showed a significant association of OSA with psoriasis (polled IRR, 2.52) across more than 5.5 million study subjects, with no statistical heterogeneity within the studies (Figure 2). After excluding one study with a high risk of bias in the representativeness of the exposed cohort—all were nurses—the association of OSA with psoriasis remained positive (pooled IRR, 2.47). A significantly increased odds for psoriasis in relation to OSA was seen in the one case-control study (adjusted OR, 13.31).

Looking Ahead

Drs. Ger and Chi note the need for future research investigating the relationship between OSA and psoriasis in patients with varying races/ethnicities and from various regions, as well as the need for studies to confirm the mechanism(s) behind the relationship between the two conditions.

In the meantime, Dr. Ger suggests that “all patients with psoriasis be made aware of their increased risk for OSA as a comorbidity that should not be overlooked. This patient population should be asked about sleep quality, and those with snoring at night, daytime sleepiness, and insomnia should be considered for polysomnography, consultation with a pulmonologists, or both. On the other hand, physicians should inquire about skin problems with their patients with OSA. Those suspected of having psoriasis should be referred to a dermatologist for further evaluation and treatment.”