Association of Arthritis Onset with Influenza: Analysis of the Canadian Early Inflammatory Arthritis Cohort

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ACR Open Rheumatol. 2019 Mar 15;1(1):63-69. doi: 10.1002/acr2.1009. eCollection 2019 Mar. Association of Arthritis Onset with Influenza: Analysis of the Canadian Early Inflammatory Arthritis Cohort.

Kudaeva F¹, Speechley M¹, Klar N¹, Schieir O², Bartlett SJ³, Bessette L⁴, Boire G⁵, Hazlewood G⁶, Hitchon CA⁷, Keystone E⁸, Tin D⁹, Thorne C⁹, Bykerk VP¹⁰, Pope JE¹¹; Canadian Early Arthritis Cohort (CATCH) investigators.
Author information

1 Schulich School of Medicine and Dentistry University of Western Ontario London Ontario Canada. 2 University of Toronto Toronto Ontario Canada. 3 McGill University Montreal Quebec Canada. 4 Centre Hospitalier Universitaire (CHU) de Qu?bec-Universit? Laval Laval Quebec Canada. 5 Centre Hospitalier Universitaire (CHU) de Sherbrooke and Universite de Sherbrooke Sherbrooke Quebec Canada. 6 University of Calgary Calgary Alberta Canada. 7 University of Manitoba Winnipeg Manitoba Canada. 8 University of Toronto and Mount Sinai Hospital Toronto Ontario Canada. 9 Southlake Regional Health Centre Newmarket Ontario Canada. 10 Hospital for Special Surgery Weill Cornell Medical College New York New York. 11 St. Joseph's Health Care London University of Western Ontario London Ontario Canada.

Abstract

Objective:

To evaluate seasonal patterns of early inflammatory arthritis (IA) onset and potential associations with IA symptom onset.
Methods:

The Canadian Early Arthritis Cohort (CATCH) is an inception cohort study of adults with early (12 months or less) IA. We used patient reports of symptom onset as a proxy of IA onset and examined the seasonal distribution of IA onset over 10 years. Influenza time series was based on laboratory-confirmed influenza A and B from the Canadian FluWatch surveillance from 2010-2016. Bivariate analysis of influenza and IA was performed using cross-correlations with different time lags and Poisson regression. IA and influenza were recorded as monthly total frequencies.
Results:

Of 2519 IA patients, 88% had confirmed rheumatoid arthritis (RA). Significantly, more IA onsets occurred in winter compared with other seasons (P = 0.03); although IA onset was more frequent in January, the difference between months was not statistically significant. Compared to months with the lowest influenza rates, months with the highest influenza rates had a statistically significant, but trivial, increase of 0.003% in the incidence of IA (incidence rate ratio (95% confidence interval): 1.00003 (1.00005; 1.000053), P = 0.02).
Conclusion:

Although IA symptom onset occurs more frequently in winter, we found that flu outbreaks were not associated with a meaningful increase in IA symptom onset in a large, well-characterized cohort of Canadian adults over 6 years.
? 2019 The Authors. ACR Open Rheumatology published by Wiley Periodicals, Inc. on behalf of American College of Rheumatology.


KEYWORDS:

Early inflammatory arthritis; influenza; rheumatoid arthritis; risk factors; time series analysis

PMID: 31777782 PMCID: PMC6858047 DOI: 10.1002/acr2.1009