BMJ Open . Clinical diagnosis of seasonal influenza by physicians: a retrospective observational study

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BMJ Open


. 2022 Jul 22;12(7):e055910.
doi: 10.1136/bmjopen-2021-055910.
Clinical diagnosis of seasonal influenza by physicians: a retrospective observational study


Hiroki Maita ¹ , Tadashi Kobayashi ² , Takashi Akimoto ² , Fumihiko Matsuoka ³ , Shigeki Funakoshi ³ , Hiroshi Osawa ² , Hiroyuki Kato ^{4 2 5}



Affiliations

• PMID: 35868823
• DOI: 10.1136/bmjopen-2021-055910

Free article

Abstract

Objective: To elucidate the diagnostic accuracy of pretest probability of influenza (%) by physicians and the factors affecting the clinical diagnosis.
Design: Retrospective, single-centre observational study.
Setting: A community primary care clinic in Japan.
Participants: The participants were recruited from a database of studies conducted during the influenza season from December 2017 to April 2019.
Primary outcome measure: Sensitivity and specificity of the physician's clinical diagnosis of influenza recorded in the medical record as pretest probability.
Results: A total of 335 patients (median age, 31 years; male, 66.6%) were analysed in this study. The area under the curve (AUC) of the physician's pretest probability was 0.77. At a cut-off value of 30%, the sensitivity and negative likelihood ratio were 92.0% (95% CI 86.7 to 95.7) and 0.19 (95% CI 0.11 to 0.33), respectively. At a cut-off value of 80%, the specificity and positive likelihood ratio were 90.8% (95% CI 85.4 to 94.6) and 4.01 (95% CI 2.41 to 6.66), respectively. The AUCs of patients who had and had not taken any medications before visiting the clinic were 0.77 (95% CI 0.69 to 0.85) and 0.78 (95% CI 0.71 to 0.84), respectively. The AUCs of patients with type A and B influenza were 0.78 (95% CI 0.72 to 0.84) and 0.76 (95% CI 0.70 to 0.82), respectively. The AUCs of vaccinated and unvaccinated patients were 0.80 (95% CI 0.72 to 0.88) and 0.76 (95% CI 0.63 to 0.89), respectively. The AUC for patients less than 12 hours after onset was 0.69 (95% CI 0.51 to 0.88), and that for patients aged younger than 6 years was 0.69 (95% CI 0.49 to 0.88).
Conclusions: The physician's pretest probability of influenza (%) may be useful for both definitive and exclusionary diagnoses within the limits of our study.

Keywords: GENERAL MEDICINE (see Internal Medicine); Infection control; PRIMARY CARE.