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Table 2 Adjusted parameter estimates (β) and p-values for quantile regression, ordinary least-squares regression, and the generalized linear mixed model

From: Using quantile regression to investigate racial disparities in medication non-adherence

  QReg OLS GLMM
  Quantile 1 Quantile 2 Quantile 3 Quantile 4     
Parameter β P β P β P β P β P β P
Intercept 38.2 0.00 49.2 0.00 72.1 0.00 82.6 0.00 88.2 0.00 89.5 0.00
NHB -3.42 0.11 -5.42 0.01 -3.1 0.00 -2.0 0.00 -1.4 0.00 -1.3 0.00
Other -6.33 0.00 -3.75 0.09 -0.9 0.34 0.5 0.36 -0.1 0.74 -0.1 0.70
NHW (REF)             
Male -11.4 0.04 -7.00 0.22 0.4 0.86 1.1 0.42 -0.5 0.58 -0.4 0.62
Age 0.24 0.01 0.27 0.00 0.2 0.00 0.1 0.00 0.1 0.00 0.1 0.00
Age-squared -0.01 0.14 -0.01 0.04 0.0 0.11 0.0 0.00 0.0 0.00 0.0 0.00
Never Married -2.84 0.45 -7.62 0.05 -0.5 0.79 -1.8 0.06 -0.9 0.16 0.9 0.13
Divorced -3.37 0.09 -5.35 0.01 -2.9 0.00 -2.6 0.00 -1.4 0.00 1.2 0.00
Married (REF)             
Employed 5.49 0.02 4.52 0.07 2.8 0.01 1.1 0.06 1.3 0.00 0.6 0.15
Retired -1.03 0.61 2.04 0.34 1.9 0.04 1.3 0.01 0.6 0.06 -0.6 0.04
Unemployed (REF)             
Cancer -8.24 0.05 -13.0 0.00 -3.1 0.10 -0.4 0.70 -1.4 0.05 -1.0 0.11
CHD 14.8 0.00 8.2 0.01 0.0 1.00 0.4 0.65 0.7 0.19 0.5 0.31
CHF 1.37 0.71 0.3 0.93 -1.0 0.54 -2.0 0.04 -0.9 0.16 -0.9 0.08
Hypertension 0.46 0.86 -0.5 0.85 -0.8 0.51 -1.6 0.02 -1.1 0.01 -0.9 0.02
Poor HbA1c 12.2 0.00 7.1 0.01 -0.6 0.58 -2.7 0.00 -1.0 0.02 -5.0 0.00
Stroke -1.60 0.75 -4.7 0.37 -0.5 0.81 -0.7 0.58 -0.6 0.47 -0.5 0.47
Bipolar -4.16 0.54 -5.1 0.47 2.3 0.45 -0.6 0.72 -0.2 0.84 0.1 0.93
GAD 1.53 0.79 -1.1 0.86 3.7 0.16 1.6 0.28 0.9 0.36 0.6 0.45
Psychoses 7.28 0.23 6.8 0.28 -3.4 0.21 0.9 0.57 0.0 1.00 -0.5 0.53
PTSD -3.30 0.40 -1.6 0.70 2.6 0.14 1.4 0.18 0.7 0.30 0.9 0.12
Substance Use 7.00 0.01 5.78 0.03 2.6 0.02 1.5 0.02 1.0 0.02 0.8 0.03
  1. NHB = Non-Hispanic Black
  2. NHW = Non-Hispanic White (Reference)
  3. Other = Other race groups
  4. β = Parameter Estimate
  5. P = p-value
  6. OLS = Ordinary Least Squares
  7. GLMM = Generalized Linear Mixed Model
  8. QReg = Quantile Regression
  9. Quantile 1 = 0.02 corresponding to a medication possession ratio (MPR) of 40%
  10. Quantile 2 = 0.04 corresponding to a medication possession ratio (MPR) of 60%
  11. Quantile 3 = 0.15 corresponding to a medication possession ratio (MPR) of 80%
  12. Quantile 4 = 0.27 corresponding to a medication possession ratio (MPR) of 90%