[Validation of a symptom scale for COVID-19 patients in ambulatory care].

BACKGROUND

A symptom scale can be useful for the standardization of clinical evaluations and follow-up of COVID-19 patients in ambultaroy care. Scale development should be accompanied by an assessment of its reliablility and validity.

OBJECTIVE

To develop and measure the psychometric characteristics of a COVID-19 symptom scale to be answered by either healthcare personnel or adult patients in ambulatory care.

MATERIAL AND METHODS

The scale was developed by an expert panel using the Delphi method. We evaluated inter-rater reliability, where we defined a good correlation if Spearman's Rho was ≥ 0.8; test-retest, where we defined a good correlation if Spearman's Rho was ≥ 0.7; factor analysis using principal component methodology; and discriminant validity using Mann-Whitney's U test. A p < 0.05 was considered statistically significant.

RESULTS

We obtained an 8 symptom scale, each symptom is scored from 0-4, with a total minimum score of 0 and a maximum of 32 points. Inter-rater reliability was 0.995 (n = 31), test-retest showed correlation of 0.88 (n = 22), factor analysis detected 4 factors (n = 40) and discriminant capacity of healthy versus sick adults was significant (p < 0.0001, n = 60).

CONCLUSIONS

We obtained a reliable and valid Spanish (from Mexico) symptom scale for COVID-19 ambulatory care, answerable by patients and health care staff.