Psoriasis May Lower Pneumonia Risk in Patients With ESRD

Despite an association between psoriasis and increased risk of acute infection, researchers have found that having the disease does not put patients with end-stage renal disease (ESRD) at a higher risk for pneumonia.

The decade’s worth of retrospective data from over 1 million patients with ESRD undergoing dialysis showed that psoriasis may actually be protective against pneumonia in these patients.

Findings were published in The American Journal of the Medical Sciences.

When accounting for a variety of factors, including age, race, sex, ethnicity, dialysis modality, Charlson Comorbidity Index (CCI), and tobacco and alcohol use, the researchers found that psoriasis was associated with a decreased risk of pneumonia (adjusted odds ratio [OR], 0.56; 95% CI, 0.53-0.59). They noted that it’s unclear why psoriasis appeared to lower the risk of pneumonia in these patients, and they hypothesize it may be attributed to the increased amount of circulating antimicrobial peptides associated with psoriasis.

Although simple models showed that psoriasis was associated with an increased risk of pneumonia (OR, 1.14, 95% CI, 1.08-1.20), the researchers explained the increased risk was attributed to higher CCI and tobacco use—present in one-third of patients—being strong confounders.

“The association of pneumonia diagnosis with tobacco use has also been found in previous studies and is likely due to direct smoke-induced damage of the respiratory tract epithelium, decreasing functional cilia,” explained the researchers, emphasizing the importance of close surveillance of patients who use tobacco. “The increased proportion of ESRD patients with pneumonia also having a diagnosis of alcohol use is also not surprising as alcohol use is a well-known risk factor for pneumonia.”

In addition to psoriasis, being of Black, Hispanic, or other race was associated with a decreased risk of pneumonia. Meanwhile, older age, being female, receiving hemodialysis, and having multiple sclerosis were associated with an increased risk. The researchers noted that pneumonia has been linked to several risk factors accounted for in the CCI, including chronic respiratory disease, HIV, cardiovascular disease, and liver disease.

Among the patients with ESRD included in the study, 6800 (0.7%) patients had a psoriasis diagnosis, and 386,000 (36%) patients had pneumonia. Compared with those without psoriasis, patients with the disease were more likely to be older and use tobacco and alcohol.

“ESRD patients with psoriasis also had increased CCI scores compared to those without psoriasis. Psoriasis is associated with many comorbidities including cardiovascular diseases, metabolic syndrome, atherosclerosis, lymphomas, and nonalcoholic fatty liver disease, many of which are included in the CCI,” described the researchers. “This association might be attributable to the inflammatory nature of psoriasis and may explain the higher CCI found in ESRD patients with psoriasis; this concurrence also suggests the necessity of controlling for such comorbidities in order to determine whether psoriasis is an independent risk factor for other illnesses in the general or ESRD population.”

Having multiple sclerosis was more likely among patients with psoriasis compared with patients without the disease, which the researchers said was not surprising due to previous research suggesting that patients with psoriasis have a significantly higher risk of developing multiple sclerosis.

Reference

Aitkens L, Waller JL, Baer SL, et al. Psoriasis and pneumonia in the end- stage renal disease population. Am J Med Sci. 2022;364(1):29-35. doi:10.1016/j.amjms.2022.03.002