Underreporting of treatment outcomes in hospitalized COVID-19 infected diabetes patients: a systematic review, meta-analysis, and meta-regression

Background: Prolonged inpatient care requirements and time constraints of research and researchers lead to the non-reporting of the treatment outcome of certain COVID-19 infected diabetes patients in published manuscripts. This study aims to quantify its global burden.  Methods: A search for citations addressing the above outcome ensued chiefly in the PubMed, Embase, and Scopus databases, irrespective of the publication date and geographical region. Recruited studies were critically appraised with the National Heart, Lung, and Blood Institute's tool. Using the random-effects meta-analysis with an exact binomial method and Freeman-Tukey double arcsine transformation, the overall and subgroup-wise weighted pooled prevalence of the missing treatment outcome data was determined. The heterogeneity and publication bias assessment utilized I2 and Chi2 statistics, and funnel plot, and Egger's test, respectively. Results: Ten publications (primarily case series; 70.0%) included in this review sourced data from 6687 COVID-19 infected inpatient diabetes patients from Asia, Australia, Europe, and North America. The global pooled prevalence of missing treatment outcome data among these patients was 33.0% (95% CI: 15.0-53.0%; I2: 99.53%; P of Chi2: <0.001). It was highest in Europe (63%; 95% CI: 61.0-66.0%). Publication bias assessment was not suggestive of any small study effect. Conclusion: A considerable proportion of crucial prognosis information of hospitalized COVID-19 patients with diabetes goes underreported. It increases the risk of biasing the contemporary COVID-19-diabetes literature. The reporting of these data in the post-publication era or postponing the primary publication until the availability of all patients' treatment outcome data, when feasible, is recommended to address this enigma