Table 4. Marginal effect of BASFI, BASDAI, or Health Status on selected AS costs.
| Covariates (Explanatory Variables) | Dependent Variables | ||||
|---|---|---|---|---|---|
| NHS Cost | GP Cost | OP Cost | IP Cost | Out of Pocket Expense | |
| Panel A: Questionnaire Data | |||||
| BASFI | 46.04 ** | 14.32 ** | 14.75 ** | 16.41* | 12.3 ** |
| (CI: 26.1, 66.0) | (CI: 7.1, 21.6) | (CI: 8.20, 21.3) | (CI: 0.04, 32.8) | (CI: 4.9, 19.8) | |
| BASDAI | 40.64 ** | 12.25 ** | 16.33 ** | 11.36 ** | 14.1 ** |
| (CI: 18.2, 63.0) | (CI: 5.9,19.3) | (CI: 9.03, 23.6) | (CI: -6.9, 29.6) | (CI: 5.8, 22.4) | |
| Health Status | -54.41 ** | -17.13 ** | -18.01 ** | -18.07 ** | -23.1 ** |
| (CI: -78.9, -30.0) | (CI: -26.0, -8.3) | (CI: -26.0, -10.0) | (CI: -38.1, 2.0) | (CI: -32.1, -14.2) | |
| Panel B: Routine Data | |||||
| BASFI | 25.1 ** | 10.7** | 6.9 ** | 9.7* | |
| (CI: 11.5, 36.6) | (CI: 7.1, 14.3) | (CI: 3.7, 10.0) | (CI: 2.3, 17.1) | ||
| BASDAI | 26.3 ** | 9.4 ** | 5.2 ** | 7.6 | |
| (CI: 11.0, 41.7) | (CI: 5.2, 13.6) | (CI: 1.6, 8.7) | (CI: -0.8, 15.9) | ||
| Health Status | -42.7 | -14.5 ** | -9.6 | -16.1 ** | |
| (CI:- 59.4, -25.9) | (CI: -19.0, -10.0) | (CI: -13.4, -5.8) | (CI: -25.2, -7.1) | ||
Note: 95% confidence intervals for the coefficients are reported in the parentheses.
** implies that coefficients are significant at 1% level of significance (* implies 5% level). For each covariate, the regressions were run separately controlling for age and sex. In the above table the marginal effects are therefore generated from running 15 specifications. Age was a significant determinant for IP costs.