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Table 2 Parameter estimates, 95% confidence intervals, standard errors for intercept, race and comorbidity in linear mixed model (LMM * ) of HbA1c using sampling and random effects Meta-regression, in for Veterans with Type 2 Diabetes (2002-2006)

From: Fitting parametric random effects models in very large data sets with application to VHA national data

Simple random sample (SRS)
Parameter Sample (%) Intercept Non-hispanic black Hispanic Other 1 Comorbidity 2 Comorbidities 3+ Comorbidities
β (95% CI) 100 7.54 (7.52, 7.55) 0.46 (0.45, 0.46) 0.29 (0.28, 0.30) 0.25 (0.23, 0.25) 0.01 (0.01, 0.02) 0.04 (0.04, 0.05) 0.11 (0.11, 0.13)
  25 7.59 (7.55, 7.61) 0.46 (0.44, 0.47) 0.31 (0.28, 0.32) 0.24 (0.22, 0.25) 0.01 (0.00, 0.02) 0.02 (0.01, 0.04) 0.10 (0.08, 0.13)
  10 7.54 (7.48, 7.58) 0.47 (0.44, 0.48) 0.30 (0.26, 0.32) 0.26 (0.23, 0.27) 0.03 (0.02, 0.05) 0.08 (0.07, 0.12) 0.08 (0.05, 0.13)
  5 7.54 (7.48, 7.62) 0.44 (0.41, 0.47) 0.28 (0.23, 0.32) 0.27 (0.24, 0.30) 0.03 (0.01, 0.06) 0.05 (0.02, 0.09) 0.13 (0.08, 0.18)
SE 100 0.0115 0.005 0.007 0.005 0.0037 0.0054 0.0079
  25 0.0115 0.005 0.007 0.005 0.0037 0.0054 0.0080
  10 0.0115 0.005 0.007 0.005 0.0037 0.0054 0.0080
  5 0.0116 0.005 0.0069 0.005 0.0037 0.0053 0.0079
Stratified random sampling (StRS)
Parameter Sample (%) Intercept Non-Hispanic Black Hispanic Other 1 Comorbidity 2 Comorbidities 3+ Comorbidities
β (95% CI) 25 7.61 (7.57, 7.63) 0.47 (0.45, 0.48) 0.28 (0.26, 0.29) 0.26 (0.24, 0.27) 0.01 (0, 0.02) 0.03 (0.02, 0.05) 0.11 (0.11, 0.15)
  10 7.58 (7.53, 7.63) 0.46 (0.43, 0.48) 0.28 (0.25, 0.30) 0.26 (0.23, 0.28) 0.0 (-0.01, 0.02) 0.05 (0.03, 0.08) 0.16 (0.13, 0.2)
  5 7.61 (7.54, 7.68) 0.38 (0.35, 0.41) 0.30 (0.26, 0.35) 0.25 (0.21, 0.28) 0.02 (0.0, 0.05) 0.05 (0.02, 0.09) 0.09 (0.05, 0.15)
SE 25 0.0111 0.0049 0.0068 0.005 0.0037 0.0054 0.0079
  10 0.0111 0.0049 0.0068 0.0049 0.0037 0.0054 0.0078
  5 0.0111 0.0050 0.0069 0.005 0.0037 0.0053 0.0079
Random effects meta-regression without VISN 13 & 14 (REMR)
Parameter** Sample (%) Intercept Non-Hispanic Black Hispanic Other 1 Comorbidity 2 Comorbidities 3+ Comorbidities
β(95% CI) 100 7.58 (7.54, 7.62) 0.45 (0.41, 0.49) 0.08, (0.04, 0.12) 0.23 (0.19, 0.27) 0.01 (-0.04, 0.05) 0.03 (-0.01, 0.07) 0.09 (0.05, 0.13)
  1. *-Independent variables used in fitting the linear mixed model were: linear time; race (non-Hispanic white reference, indicator variables); sex (female reference); marital status (single reference), service disability percentage, residence status (urban/rural, rural reference), VISN region (Northeast, Mid-Atlantic, South, Midwest, and West), and number of comorbidities (1, 2, or 3+; none reference).
  2. ** Veteran Integrated Service Networks (VISNs) 13 and 14 are excluded in all these models.
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BMC Medical Research Methodology

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