RESUMO
Background: COVID-19 infectivity has been linked to various background factors, but there is no data on preCOVID determinants of COVID-19 diagnosis by the clinician, RT-PCR, and diagnosis by both methods. In an adult representative sample with pre-COVID data, we aimed to identify determinants of subsequent COVID-19 diagnosis by the clinician and RT-PCR. Method(s): In the cohort of 42,621 adults, 5,705 were diagnosed with COVID-19 by a clinician based on ICD-10 codes and 3,936 using RT-PCR. Pre-COVID data were available for several demographic factors, socio-economic (SES) factors, and several indicators of respiratory symptoms. Result(s): In total, 6,560 (15.4%) were diagnosed with COVID-19 by either clinician or RT-PCR;47% had both clinician diagnosis and RT-PCR;40% had clinician diagnosis but not RT-PCR confirmation;and 13% had only RTPCR confirmation. Proportion of those diagnosed by a clinician increased by age, but those of age >= 60 years were less likely to be confirmed with RT-PCR than those younger. Clinician diagnosis of COVID-19 did not differ by smoking, BMI, childhood on a farm, education, SES, or respiratory symptoms, but those with >= 2 co-morbidities were more likely to be diagnosed than those with <2 co-morbidities. For RT-PCR, ex-smokers, those who grew up on a farm, those with less high school education, those with respiratory symptoms, asthma, COPD, and >=2 co-morbidities were less likely to be diagnosed with COVID-19. Conclusion(s): Pre-COVID factors may influence COVID diagnosis and these act differentially for clinician-based diagnosis and based on RT-PCR. Such information can be useful for planning future screening efforts for COVID or other similar outbreaks.
RESUMO
Background: Due to the high transmissibility of SARS-Cov-2, the virus causing COVID-19, accurate diagnostic methods are essential for effective infection control, but the gold standard method of real-time polymerase chain reaction (RT-PCR) is costly, slow, and test capacity has at times been insufficient. Method(s): Diagnosis data were retrieved from registers, based on positive RT-PCR or ICD-10 codes set by clinicians. Through linkage to a population-representative adult cohort in Sweden, we assessed the accuracy of clinician diagnosis against RT-PCR, stratified by number and severity of comorbidities. Result(s): A total of 42,621 subjects were included. Of these, 6,560 had COVID-19. Clinician diagnosis was found in 5,705 subjects, while 3,936 had a positive RT-PCR and 3,081 got diagnosed with both methods. Of those with at least one comorbidity, sensitivity for clinician diagnosis ranged from 69% (95% CI 44-86) for those with two "severe" comorbidities (diabetes and chronic obstructive pulmonary disease) to 84% (95% CI 73-91) for those with two "moderately severe" comorbidities (asthma and hypertension). Specificity was > 90% for all comorbidity groups. Youden's index increased slightly with the number of comorbidities in both "severe" and "moderately severe" categories, but for those with "light" comorbidities (eczema, rhinitis, sleep disorders), it was the lowest with >=2 comorbidities (69% (95% CI 66-72)). Youden's index was 71% (95% CI 70-72) for those with no comorbidities and 71% (95% 69-73) for the whole cohort. Conclusion(s): Clinicians identify non-cases to a high degree, but RT-PCR is needed for adequate sensitivity, regardless of comorbidity.
RESUMO
Background: Whilst the gold standard real-time polymerase chain reaction (RT-PCR) is costly and can take time to obtain results, there is a dearth of data comparing clinician diagnosis based on recommended ICD codes and RTPCR. Aim(s): In this study, we compared clinician diagnosis of COVID-19 with RT-PCR in a general adult population and evaluated any differences in accuracy by age, gender, pre-COVID-19 BMI, and obstructive airway diseases. Material(s) and Method(s): Data from a cohort of 42,621 adult-representative samples in Sweden, included 5705 clinician-diagnosed and 3936 RT-PCR-diagnosed COVID-19 patients. Using RT-PCR as the reference standard, estimates of the accuracy of clinician's diagnosis were determined. Result(s): The sensitivity and specificity of clinician diagnosis in identifying COVID-19 was 78% (95%CI 77-80%) and 93% (95%CI 93-93%), respectively. The positive predictive value was 54% (95%CI 53-55%), negative predictive value was 98% (95%CI 98-98%) and the Youden's Index was 71% (95%CI 70-72%). These accuracy measures were similar between men and women, across age groups, BMI categories, and between patients with and without asthma. However, while the specificity, negative predictive value, and Youden's index were similar between patients with and without COPD, the sensitivity was slightly higher in patients with COPD (84%, 95%CI 74-90%) than those without (78%, 95%CI 77-79%) COPD. Conclusion(s): The accuracy of clinician's diagnosis for COVID-19 is adequate, regardless of gender, age, pre-COVID19 BMI, asthma, and COPD, thus can be used for screening purposes to supplement RT-PCR.