Results of instrumental variable analyses to estimate the association of HDHPs with the probability of umbilical hernia repair being performed before age 4 years or after age 5 years
| Risk difference (95% CI) | P value | |
| Surgery before age 4 years | ||
| Total cohort | 0.024 (–0.130 to 0.177) | 0.76 |
| Children ≤10 years of age | 0.040 (–0.126 to 0.206) | 0.64 |
| Surgery after age 5 years | ||
| Total cohort | 0.014 (–0.157 to 0.185) | 0.87 |
| Children ≤10 years of age | −0.026 (–0.197 to 0.145) | 0.77 |
The results are from two-stage least squares regression models with heteroskedasticity-robust SEs that included MSA, year, child sex, the presence of any chronic condition, whether a concurrent surgical procedure was performed, and the MSA/year-level median household income in households with children and MSA/year-level percentage of children of non-Hispanic white race/ethnicity.
HDHP, high deductible health plan; MSA, metropolitan statistical area.