Association between vitamin D supplementation and COVID-19 infection and mortality.

Vitamin D deficiency has long been associated with reduced immune function that can lead to viral infection. Several studies have shown that Vitamin D deficiency is associated with increases the risk of infection with COVID-19. However, it is unknown if treatment with Vitamin D can reduce the associated risk of COVID-19 infection, which is the focus of this study. In the population of US veterans, we show that Vitamin D2 and D3 fills were associated with reductions in COVID-19 infection of 28% and 20%, respectively [(D3 Hazard Ratio (HR) = 0.80, [95% CI 0.77, 0.83]), D2 HR = 0.72, [95% CI 0.65, 0.79]]. Mortality within 30-days of COVID-19 infection was similarly 33% lower with Vitamin D3 and 25% lower with D2 (D3 HR = 0.67, [95% CI 0.59, 0.75]; D2 HR = 0.75, [95% CI 0.55, 1.04]). We also find that after controlling for vitamin D blood levels, veterans receiving higher dosages of Vitamin D obtained greater benefits from supplementation than veterans receiving lower dosages. Veterans with Vitamin D blood levels between 0 and 19 ng/ml exhibited the largest decrease in COVID-19 infection following supplementation. Black veterans received greater associated COVID-19 risk reductions with supplementation than White veterans. As a safe, widely available, and affordable treatment, Vitamin D may help to reduce the severity of the COVID-19 pandemic.

The Role of Social Support in Telehealth Utilization Among Older Adults in the United States During the COVID-19 Pandemic.

Background: Older adults may experience a significant digital divide and need support with using technology to transition to telehealth. This study examines the role of social support for telehealth utilization among older adults during the COVID-19 pandemic. Materials and Methods: We used data from the COVID-19 Sample Person Interview to the National Health and Aging Trends Study. Using logistic regression, we measured the association between telehealth utilization and social support. Results: Nearly one in five respondents used telehealth during the COVID-19 pandemic (weighted %: 20.6 [585/3188]). Currently living with family or friends and receipt of technical support were associated with telehealth utilization. Among residents of an assisted living facility, those who received communications technology support from the facility were more likely to use telehealth. Conclusion: Health care providers and policies should aim to reduce barriers to telehealth among older adults, with efforts such as digital literacy support and training.

Association Between Primary Care Practice Telehealth Use and Acute Care Visits for Ambulatory Care-Sensitive Conditions During COVID-19.

Importance: During the COVID-19 pandemic, many primary care practices adopted telehealth in place of in-person care to preserve access to care for patients with acute and chronic conditions. The extent to which this change was associated with their rates of acute care visits (ie, emergency department visits and hospitalizations) for these conditions is unknown. Objective: To examine whether a primary care practice's level of telehealth use is associated with a change in their rate of acute care visits for ambulatory care-sensitive conditions (ACSC visits). Design, Setting, and Participants: This retrospective cohort analysis used a difference-in-differences study design to analyze insurance claims data from 4038 Michigan primary care practices from January 1, 2019, to September 30, 2020. Exposures: Low, medium, or high tertile of practice-level telehealth use based on the rate of telehealth visits from March 1 to August 31, 2020, compared with prepandemic visit volumes. Main Outcomes and Measures: Risk-adjusted ACSC visit rates before (June to September 2019) and after (June to September 2020) the start of the COVID-19 pandemic, reported as an annualized average marginal effect. The study examined overall, acute, and chronic ACSC visits separately and controlled for practice size, in-person visit volume, zip code-level attributes, and patient characteristics. Results: A total of nearly 1.5 million beneficiaries (53% female; mean [SD] age, 40 [22] years) were attributed to 4038 primary care practices. Compared with 2019 visit volumes, median telehealth use was 0.4% for the low telehealth tertile, 14.7% for the medium telehealth tertile, and 39.0% for the high telehealth tertile. The number of ACSC visits decreased in all tertiles, with adjusted rates changing from 24.3 to 14.9 per 1000 patients per year (low), 23.9 to 15.3 per 1000 patients per year (medium), and 27.5 to 20.2 per 1000 patients per year (high). In difference-in-differences analysis, high telehealth use was associated with a higher ACSC visit rate (2.10 more visits per 1000 patients per year; 95% CI, 0.22-3.97) compared with low telehealth practices; practices in the middle tertile did not differ significantly from the low tertile. No difference was found in ACSC visits across tertiles when acute and chronic ACSC visits were examined separately. Conclusions and Relevance: In this cohort study that used a difference-in-differences analysis, the association between practice-level telehealth use and ACSC visits was mixed. High telehealth use was associated with a slightly higher overall ACSC visit rate than low telehealth practices. The association of telehealth with downstream care use should be closely monitored going forward.