Epidemiology, risk factors and clinical outcome of community-acquired pneumonia in severely immunosuppressed patients: a comprehensive analysis from the multinational, prospective CAPNETZ Cohort.

Abstract

Purpose: Despite growing evidence that immunosuppression (IS) influences aetiology and prognosis of community-acquired pneumonia (CAP), there remains a lack of data from representative multicentre studies.

Methods: The multinational prospective CAPNETZ study includes patients with CAP and HIV since 2017, and with other causes of IS since 2020. We present the first comprehensive analysis of patients with CAP and IS (HIV with low CD4 cells, systemic steroids, immunosuppressive drugs, antineoplastic treatment, neutropenia, primary immunodeficiency, transplantation, haematological neoplasia) included within CAPNETZ until December 2023. IS cases were matched 1:1 with non-IS patients. The primary end-point was 30-day mortality and/or organ replacement therapy. Additionally, cases of CAP caused by non-core respiratory pathogens (NCRPs) according to an international consensus were evaluated. Univariate and multivariate risk factor analyses and evaluation of predictive scores by receiver operating characteristic analysis were performed.

Results: We included 232 patients with IS, most commonly after antineoplastic therapy (37.5%), systemic steroids (36.2%) and immunosuppressive drugs (35.8%). 10.3% reached the primary end-point. Overall, IS was not associated with prognosis compared to matched non-IS patients, but patients with immunosuppressive drugs had a significantly lower risk. The qSOFA, CRB-65 and CURB-65 scores showed limited prediction (area under the curve 0.57-0.64) and insufficient sensitivity for the primary end-point. CAP caused by NCRPs occurred in 16.4% in IS and was associated with transplantation, previous anti-infective treatment and intensive care unit admission, but SARS-CoV-2, Haemophilus influenzae and Streptococcus pneumoniae were the most common pathogens in both groups.

Conclusion: This study demonstrates the relevance and heterogeneity of CAP in IS and highlights the need for individualised risk stratification and treatment.