Recruitment of population-based controls for ALS cases from the National ALS Registry.

Objective: In 2010, the United States Agency for Toxic Substances and Disease Registry (ATSDR) created the National ALS Registry (Registry) to examine the epidemiology of ALS and potential risk factors. We are currently recruiting population-based controls for an epidemiologic case-control study to examine ALS environmental risk factors using this Registry. To date, we have recruited 181 non-diseased, population-based controls for comparison to Registry cases (n = 280). Here we report our recruitment methods for controls and the associated response rates and costs. Methods: Eligible ALS cases had complete risk factor survey data, DNA analysis, and blood concentrations of persistent organic pollutants (POPs). Age, sex, and county-matched controls were identified from commercial/consumer databases using a targeted landline phone sample. Eligible controls were consented, surveyed, and mailed the POPs' blood analysis consent form. Once consented, phlebotomy was scheduled. Results: We mailed 3760 recruitment letters for 181 potential case-matches across 42 states between 9/2018 and 3/2020. After making phone contact and determining eligibility, 146 controls agreed to participate (response rate = 11.4%, cooperation rate = 22.8%). To date, 127 controls completed the survey and bloodwork. Though controls were matched to cases on age, sex, and county, unmatched characteristics (e.g. smoking) did not differ statistically. Interviewing and incentive costs are estimated at $211.85 per complete participation. Conclusions: Recruiting matched population-based controls for comparison to cases from the Registry for a study involving completion of a detailed survey and blood specimen provision is relatively feasible and cost effective. This recruitment method could be useful for case-control studies of other rare disorders.

Gender-based disparities in COVID-19 patient outcomes.

Studies reported to date suggest that men with COVID-19 have more severe disease and worse outcomes when compared with women. The explanation for this finding is not entirely clear. The goal of this study was to compare clinical characteristics, inflammatory biomarkers and clinical outcome between men and women. This retrospective study included patients with COVID-19 admitted to 10 Virginia hospitals from January 1, 2020, to June 15, 2020. Demographic data, comorbidities, and inflammatory markers, including C reactive protein (CRP), D-dimer, ferritin, and the neutrophil:lymphocyte ratio, as well as patient outcomes, were compared between men and women. During the study period, 701 patients with PCR-confirmed COVID-19 infection were admitted. The patient's mean age was 61±17 years. There were 370 men (52.8%). There was no difference in age, racial distribution, and comorbidities in the male patients compared with the female patients. However, both the baseline and peak levels of CRP and ferritin were significantly higher in men as compared with women. While the baseline D-dimer was similar between the sexes, men had a significantly higher maximal D-dimer. Men had evidence of greater disease severity, with a significantly greater admission to the intensive care unit and borderline higher hospital mortality. Our study supports the observation that COVID-19 causes more severe disease in men. The greater disease severity in men was not due to the effect of age or comorbidities; however, in keeping with experimental studies, men had evidence of a heightened inflammatory response, likely contributing to disease severity.