3.1.2. Models Predicting Total Mortality Incidence
Models of key predictors of COVID-19 deaths by census tract in
each of the two phases are presented in Figure 1 (right points, in
darker blue). Overall, tract-level characteristics consistently
associated with increased risk of COVID-19 mortality included population
proportions of Black or Latinx residents, share of population aged over
80 years, and number of LTCF beds per capita. The only variable
consistently associated with decreased risk of census-tract mortality
rates was proportion of undergraduate students. Crowded housing,
proportion of AIAN residents, and rate of uninsured individuals were not
statistically significantly associated with tract-level COVID-19 case
deaths in either phase. While most variables were statistically stable
between Phase 1 and Phase 2 (i.e., consistent directionality and
significance), proportion of essential workers went from not
statistically significant in Phase 1 (IRR: 0.98 [0.90, 1.06]) to
significantly positive in Phase 2 (IRR: 1.08 [1.03, 1.14]), and
housing density went from not statistically significant (0.94 [0.85,
1.03]) to significantly negative (0.89 [0.83, 0.97]) . Other
variables had substantive attenuations in their point estimates between
Phase 1 and Phase 2 (i.e., greater than 10% change toward the null):
IRRs decreased for proportion of Black residents (decreasing from 1.20
[1.11, 1.30] in Phase 1 to 1.07 [1.01, 1.13] in Phase 2) and
LTCF beds per capita (decreasing from 2.53 [2.33, 2.74] to 1.70
[1.62, 1.78]), while IRRs increased for proportion of
residents aged 20 years or younger, albeit to become non-significant
(increasing from 0.90 [0.82, 0.98] to 0.98 [0.92, 1.04]).