Self-reported symptoms in French primary care SARS-CoV-2 patients: association with gender and age group.

INTRODUCTION: The early identification of COVID-19 patients is of outmost importance in the current pandemic. As with other pathogens, presenting symptoms of SARS-CoV-2 may vary, depending on sociodemographic factors. We aimed to describe the clinical characteristics of COVID-19 patients by age/gender and to assess whether the diagnostic performance of these symptoms varied according to these variables. METHODS: We analysed data from a cross-sectional study involving primary care patients undergoing RT-PCR testing in Lyon, France. Among patients who tested positive, we examined whether there was an association between age/gender and various symptoms. In addition, we calculated the diagnostic performance of the most specific symptoms (smell/taste disorder). RESULTS: Among 1543 consecutive patients, 253 tested positive (16%). There were significant age/gender-related differences in symptoms. In middle-aged women, the diagnostic performance of smell/taste disorders were AUC = 0.65 [95%CI 0.59-0.71] and PPV = 72% [95%CI 53-87%], that is higher than in the entire sample (smell/taste disorders: AUC = 0.59 [95%CI 0.57-0.62] and PPV = 57% [95%CI 47-67%]. In contrast, the negative predictive values of smell/taste disorders were similar in both groups (85% [95%CI 81-89%] for middle-age women and 86% [95%CI 85-88%] for the entire sample). CONCLUSION: We found significant age/gender-related differences in the clinical characteristics of COVID-19 patients. Screening strategies based on smell/taste disorders performed better in middle-aged women, but could not ensure a diagnosis of COVID-19 in any subgroup of patients. Future diagnostic strategies should use age/gender differentiated approaches.

Cross sectional study of the clinical characteristics of French primary care patients with COVID-19.

The early identification of patients suffering from SARS-CoV-2 infection in primary care is of outmost importance in the current pandemic. The objective of this study was to describe the clinical characteristics of primary care patients who tested positive for SARS-CoV-2. We conducted a cross-sectional study between March 24 and May 7, 2020, involving consecutive patients undergoing RT-PCR testing in two community-based laboratories in Lyon (France) for a suspicion of COVID-19. We examined the association between symptoms and a positive test using univariable and multivariable logistic regression, adjusted for clustering within laboratories, and calculated the diagnostic performance of these symptoms. Of the 1561 patients tested, 1543 patients (99%) agreed to participate. Among them, 253 were positive for SARS-CoV-2 (16%). The three most frequently reported 'ear-nose-throat' and non-'ear-nose-throat' symptoms in patients who tested positive were dry throat (42%), loss of smell (36%) and loss of taste (31%), respectively fever (58%), cough (52%) and headache (45%). In multivariable analyses, loss of taste (OR 3.8 [95% CI 3.3-4.4], p-value < 0.001), loss of smell (OR 3.0 [95% CI 1.9-4.8], p < 0.001), muscle pain (OR 1.6 [95% CI 1.2-2.0], p = 0.001) and dry nose (OR 1.3 [95% CI 1.1-1.6], p = 0.01) were significantly associated with a positive result. In contrast, sore throat (OR 0.6 [95% CI 0.4-0.8], p = 0.003), stuffy nose (OR 0.6 [95% CI 0.6-0.7], p < 0.001), diarrhea (OR 0.6 [95% CI 0.5-0.6], p < 0.001) and dyspnea (OR 0.5 [95% CI 0.3-0.7], p < 0.001) were inversely associated with a positive test. The combination of loss of taste or smell had the highest diagnostic performance (OR 6.7 [95% CI 5.9-7.5], sensitivity 44.7% [95% CI 38.4-51.0], specificity 90.8% [95% CI 89.1-92.3]). No other combination of symptoms had a higher performance. Our data could contribute to the triage and early identification of new clusters of cases.

Simple fluorescent PCR assay for discriminating FRAXA fully mutated females from normal homozygotes.

Fragile X syndrome linked to the FRAXA locus is the most common inherited genetic disease accounting for mental retardation and is usually caused by the expansion of an unstable CGG repeat in the first exon of the FMR1 gene on the X chromosome. Despite its robustness, Southern blot is not suitable for large-scale routine screening as part of neuropediatric practice. PCR appears as an interesting alternative, and various protocols have been successfully applied to molecular screening in mentally retarded boys and girls. Unfortunately, as of this date these protocols are unable to detect the expanded allele in FRAXA females reliably, thereby failing to discriminate between fully mutated females from normal homozygotes. Therefore, we opted for an alternative approach in designing a semiquantitative PCR assay, based on the amplification of the sole wild-type allele. This method allowed us to detect the presence of one or two normal alleles with the same sizes, thereby discriminating between a FRAXA fully mutated female or a normal homozygote, respectively. A trial on 95 DNA samples from normal and mutated females demonstrated the reliability of the procedure. We believe this simple PCR assay is a powerful approach that would reduce the recourse to Southern blotting in females with mental retardation of unknown etiology.