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Prophylactic effect of sulfasalazine against Pneumocystis pneumonia in patients with rheumatoid arthritis: A nested case-control study

T. Nunokawa, N. Yokogawa, K. Shimada, S. Sugii, J. Nishino, M. Gosho, Y. Wagatsuma, S. Tohma

Seminars in Arthritis & Rheumatism, 2019

18,668 participants · 19 citations

Abstract

OBJECTIVES

To evaluate the prophylactic effect of sulfasalazine against Pneumocystis jirovecii pneumonia (PJP) among rheumatoid arthritis (RA) patients.

METHODS

We used a nationwide Japanese multicenter RA database to extract data from 2005 and 2014. To identify PJP cases, we selected patients hospitalized for PJP and verified their diagnosis. Two control groups, one unmatched and the other matched for age, sex, glucocorticoid, methotrexate, and tacrolimus dosage, and the use (and type, if used) of biological disease-modifying antirheumatic drug were selected by incidence-density sampling. The odds ratios for PJP associated with sulfasalazine use and other clinical factors were estimated by exact and standard conditional logistic regression.

RESULTS

From 18,668 participants, 60 cases, 356 unmatched controls, and 337 matched controls were selected. None of the cases received sulfasalazine before PJP onset. A comparison of the cases with the unmatched controls showed that sulfasalazine use carried a decreased risk of PJP (adjusted odds ratio 0.18, 95% confidence interval 0.00-0.92). A comparison of the cases and matched controls also showed that sulfasalazine use had a decreased risk of PJP (0.08, 0.00-0.36). In an analysis of the cases and unmatched controls who did not receive sulfasalazine, an increased risk of PJP was associated with lung disease (3.88, 1.89-7.95) and the use of glucocorticoid (5.71, 2.68-12.19), methotrexate (5.25, 2.01-13.74), and tumor necrosis factor…

How strong is the evidence?

Evidence Hub reads this as a case-control, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause. Reported size: 18,668 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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