TABLE 3.
Sensitivity analyses
| Adjusted discontinuity above versus below Medicaid income eligibility thresholds | ||||
|---|---|---|---|---|
| Adjusted only for state fixed effects and year fixed effects a | Excluding 8 states with emergency‐only coverage of dental services in 2018 b , c | Bandwidth of ±50 percentage points above and below Medicaid threshold b | Bandwidth of ±100 percentage points above and below Medicaid threshold b | |
| Dependent variable | Estimate (95% confidence interval) | |||
| Primary outcomes | ||||
| Enrolled in Medicaid for ≥1 month of the year, % d | −29.1 (−34.7, −23.4) | −28.2 (−33.8, −22.7) | −27.8 (−34.5, −21.2) | −30.5 (−35.0, −26.0) |
| Difficulty getting dental care due to cost or insurance coverage, % d | 5.0 (0.2, 9.8) | 4.4 (−0.5, 9.4) | 5.4 (−0.7, 11.6) | 5.2 (1.1, 9.3) |
| Number of annual dental visits per beneficiary e | 0.04 (−0.20, 0.28) | 0.01 (−0.25, 0.26) | 0.04 (−0.27, 0.35) | −0.05 (−0.26, 0.17) |
| Out‐of‐pocket dental care costs ≥$100, % e | 4.7 (−2.2, 11.7) | 4.0 (−2.5, 10.5) | 3.3 (−4.7, 11.2) | 5.2 (−0.5, 10.9) |
| Secondary outcomes | ||||
| Difficulty getting dental care due to factors other than cost or insurance coverage, % d | −1.6 (−4.4, 1.3) | −1.8 (−4.9, 1.3) | −1.5 (−5.1, 2.1) | −0.3 (−2.8, 2.2) |
| Enrolled in a Medicare Advantage plan for ≥1 month of the year, % d | 0.3 (−5.8, 6.4) | 0.0 (−6.4, 6.4) | 4.5 (−3.2, 12.2) | 2.4 (−3.0, 7.8) |
Estimated discontinuity in the outcome above versus below state‐specific Medicaid eligibility thresholds (pooled across states), adjusted for state fixed effects, year fixed effects, and survey weights. Confidence intervals and p‐values calculated using used robust standard errors adjusted to account for clustering within respondents across survey years.
Estimated discontinuity in the outcome above versus below state‐specific Medicaid eligibility thresholds (pooled across states), adjusted for respondent characteristics and the county‐level supply of dentists per 1000 residents (as shown in Table 1), state fixed effects, year fixed effects, and survey weights. Dividing the estimated discontinuity by the mean or proportion of that outcome gives the effect of the Medicaid coverage cliff in relative terms. Confidence intervals and p‐values calculated using used robust standard errors adjusted to account for clustering within respondents across survey years.
The states whose Medicaid programs covered emergency‐only dental services for adults in 2018 were: Arizona, Georgia, Hawaii, Nevada, New Hampshire, Oklahoma, Utah, and West Virginia.
Analyses limited to community‐dwelling Medicare beneficiaries in the 2016–2019 MCBS. In the first column of results (analyses adjusted only for state fixed effects and year effects), the sample consisted of 7508 respondent‐years, representing 26,776,719 beneficiary‐years in the community‐dwelling Medicare population. In the second column of results, which excluded states with emergency‐only Medicaid dental coverage, our sample consisted of 6578 respondent‐years, representing 23,348,276 beneficiary‐years in the community‐dwelling Medicare population. In the third column of results based on a bandwidth of ±50 percentage points, the sample consisted of 5395 respondent‐years, representing 19,206,140 beneficiary‐years in the community‐dwelling Medicare population. In the fourth column of results based on a bandwidth of ±100 percentage points, the sample consisted of 9611 respondent‐years, representing 34,566,347 beneficiary‐years in the community‐dwelling Medicare population.
Analyses based on the MCBS Cost Supplement, which is fielded on a subsample of MCBS respondents. We used survey weights in the Cost Supplement file to weight the subsample to be nationally representative of the community‐dwelling Medicare population. In the first column of results (analyses adjusted only for state fixed effects and year effects), the sample consisted of 3641 respondent‐years, representing 22,482,340 beneficiary‐years in the community‐dwelling Medicare population. In the second column of results, which excluded states with emergency‐only Medicaid dental coverage, our sample consisted of 3215 respondent‐years, representing 19,667,548 beneficiary‐years in the community‐dwelling Medicare population. In the third column of results based on a bandwidth of ±50 percentage points, the sample consisted of 2618 respondent‐years, representing 16,327,399 beneficiary‐years in the community‐dwelling Medicare population. In the fourth column of results based on a bandwidth of ±100 percentage points, the sample consisted of 4620 respondent‐years, representing 28,858,418 beneficiary‐years in the community‐dwelling Medicare population.