Skip to main content

Table 3 Two-part regression model for health care costs

From: Determinants of health care costs in the senior elderly: age, comorbidity, impairment, or proximity to death?

Predictor Probit model GLM model
Coefficient (95% confidence interval) p value Coefficient (95% confidence interval) p value
Age
 Single year −0.04 (−0.05 to −0.04) <0.001 0.001 (−0.003 to 0.006) 0.543
Gender
 Female 0.29 (0.19–0.39) <0.001 −0.12 (−0.35 to 0.11) 0.289
Age group (years)
 80–84 Ref. Ref.
 85–89 0.09 (−0.01 to 0.19) 0.089 0.35 (0.05–0.65) 0.024
 90–94 0.04 (−0.09 to 0.17) 0.515 0.42 (0.18–0.67) 0.001
 95–99 −0.09 (−0.27 to 0.09) 0.320 0.31 (0.02–0.60) 0.039
 100+ −0.94 (−1.23 to −0.64) <0.001 0.40 (−0.20 to 1.01) 0.192
Proximity to death
 Year before death (YD) 0.79 (0.65–0.93) <0.001 1.46 (1.24–1.68) <0.001
Age group × year before death (YD) interaction
 80–84.YD Ref. Ref.
 85–89.YD 0.19 (0.11–0.26) <0.001 −0.10 (−0.18 to −0.02) 0.012
 90–94.YD 0.40 (0.32–0.47) <0.001 −0.23 (−0.31 to −0.16) <0.001
 95–99.YD 0.75 (0.66–0.85) <0.001 −0.29 (−0.38 to −0.20) <0.001
 100+ .YD 1.74 (1.58–1.90) <0.001 −0.38 (−0.55 to −0.20) <0.001
Comorbidity category
 0 Ref. Ref.
 1–3 1.55 (1.46–1.65) <0.001 0.48 (0.25–0.71) <0.001
 4–6 2.25 (2.15–2.35) <0.001 0.93 (0.70–1.16) <0.001
 7–9 2.27 (2.08–2.46) <0.001 1.34 (1.10–1.58) <0.001
Impairment category
 0 Ref. Ref.
 1–3 0.40 (0.34–0.46) <0.001 0.06 (−0.06 to 0.18) 0.305
 4–6 0.54 (0.44–0.65) <0.001 0.44 (0.31–0.56) <0.001
 7–10 0.75 (0.39–1.11) <0.001 0.73 (0.53–0.93) <0.001
Constant 3.53 (2.99–4.08) <0.001 6.90 (6.46–7.35) <0.001
Interactions
 Gender × age χ 2 = 18.47, df = 4 <0.001 χ 2 = 6.23, df = 4 0.1826
 Gender × MM χ 2 = 35.51, df = 3 <0.001 χ 2 = 1.12, df = 3 0.7727
 Gender × MI χ 2 = 5.94, df = 3 0.1147 χ 2 = 7.96, df = 3 0.0469
 Age × MM χ 2 = 76.19, df = 12 <0.001 χ 2 = 60.44, df = 12 <0.001
 Age × MI χ 2 = 66.10, df = 12 <0.001 χ 2 = 30.46, df = 12 0.0024
 YD × gender χ 2 = 9.35, df = 1 0.0022 χ 2 = 0.00, df = 1 0.9871
 YD × age χ 2 = 630.85, df = 4 <0.001 χ 2 = 57.73, df = 4 <0.001
 YD × MM χ 2 = 259.55, df = 3 <0.001 χ 2 = 28.71, df = 3 <0.001
 YD × MI χ 2 = 66.28, df = 3 <0.001 χ 2 = 71.43, df = 3 <0.001