A latent class model with covariates indicated the existence of heterogeneous preferences regarding the landscape attributes, with attitude variables being significant determinants of heterogeneity.
Where heterogeneity was shown, we investigated variation in sensitivity and specificity by adding to the meta-analysis models prespecified covariates indicating acute care setting of presentation, assay of natriuretic peptide used in the study cohort, prevalence of acute heart failure, and overall study quality.
Regression models adjusted for covariates indicated a significant positive association of tree canopy coverage with diagnosed asthma at 7 years of age (adjusted RR = 1.17; 95% CI: 1.02, 1.33) consistent with a 17% increase in the prevalence of asthma with each SD increase in tree canopy coverage (for tree canopy coverage, the SD was 8%).
Significant effects and signs of coefficients from model 1a (only attributes) persist in model 1b (attributes and covariates), indicating that estimates are robust to the inclusion of other variables.
To compare index tests, we extended the bivariate model with a covariate indicating the type of index test.
Neither of the models containing CPUE as a covariate received much statistical support, but in general all models containing CPUE as covariate indicated a negative effect (density dependence).
Among subjects with a hematologic condition, results from Cox proportional hazards regression models, in which splenectomy was modeled as a time-dependent covariate, indicated that the risk of death was significantly higher for patients who underwent splenectomy compared with those who did not (Table 2).
As the fall rate is expected to change with total time, the Andersen-Gill model with a single binary covariate indicating the randomized intervention will be applied, and the null hypothesis of no intervention effect, H0:{ β=0}, is to be tested at a two-sided significance level of 5%%.
Previous educational attainment is measured at a time-point prior to initiation of these substances; high levels of attenuation within this covariate model would indicate a problem with reverse causation.
To explore this, we also fitted alternative models with a time-updated covariate indicating when children were protected by posttreatment prophylaxis, rather than stratifying on event number.
