The prognostic value of serological titres for clinical outcomes during treatment and follow-up of patients with chronic Q fever.
Clin Microbiol Infect 2021;
27:1273-1278. [PMID:
33813120 DOI:
10.1016/j.cmi.2021.03.016]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/06/2021] [Accepted: 03/14/2021] [Indexed: 12/19/2022]
Abstract
OBJECTIVES
We assessed the prognostic value of phase I IgG titres during treatment and follow-up of chronic Q fever.
METHODS
We performed a retrospective cohort study to analyse the course of phase I IgG titres in chronic Q fever. We used a multivariable time-varying Cox regression to assess our primary (first disease-related event) and secondary (therapy failure) outcomes. In a second analysis, we evaluated serological characteristics after 1 year of therapy (fourfold decrease in phase I IgG titre, absence of phase II IgM and reaching phase I IgG titre of ≤1:1024) with multivariable Cox regression.
RESULTS
In total, 337 patients that were treated for proven (n = 284, 84.3%) or probable (n = 53, 15.7%) chronic Q fever were included. Complications occurred in 190 (56.4%), disease-related mortality in 71 (21.1%) and therapy failure in 142 (42.1%) patients. The course of phase I IgG titres was not associated with first disease-related event (HR 1.00, 95% CI 0.86-1.15) or therapy failure (HR 1.02, 95% CI 0.91-1.15). Similar results were found for the serological characteristics for the primary (HR 0.97, 95% CI 0.62-1.51; HR 1.12, 95% CI 0.66-1.90; HR 0.99, 95% CI 0.57-1.69, respectively) and secondary outcomes (HR 0.86, 95% CI 0.57-1.29; HR 1.37, 95% CI 0.86-2.18; HR 0.80, 95% CI 0.48-1.34, respectively).
DISCUSSION
Coxiella burnetii serology does not reliably predict disease-related events or therapy failure during treatment and follow-up of chronic Q fever. Alternative markers for disease management are needed, but, for now, management should be based on clinical factors, PCR results, and imaging results.
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