Table A1.
Model selection. The objective function change associated with using different baseline hazard functions and other explanatory variables is shown
| Explanatory variables | Deaths at EOT n= 98 | Disability n= 364 | Cognitive impairment n= 89 | Depression n= 183 |
|---|---|---|---|---|
| Change in Objective Function Values (significance) | ||||
| Ln(time) (Weibull)+ | 33 (****) | 29 (****) | 8 (***) | 35 (****) |
| Time (Gompertz)#+ | 25 (****) | 89 (****) | 1 (NS) | 84 (****) |
| Time + Ln(time) + | 35 (****) | 90 (****) | 10 (**) | 84 (****) |
| Ageξ+ | 29 (****) | 18 (****) | 36 (****) | 0 (NS) |
| Time + age (Base)+ | 67 (****) | 104 (****) | 37 (****) | 84 (****) |
| Base + Female | 9 (*) | 0 (NS) | 1 (NS) | 0 (NS) |
| Base + Smoker | 1 (NS) | 3 (NS) | 1 (NS) | 0 (NS) |
| Base + dominant motor subtypes | 10 (*) | 5 (NS) | 2 (NS) | 7 (NS) |
| Base + Levodopa& | 13 (***) | 26 (****) | 3 (NS) | 4 (*) |
| Base + Selegiline& | 3 (NS) | 70 (****) | 4 (*) | 20 (****) |
| Predicted disease status | ||||
| Base + UPDRS | 86 (****) | 760 (****) | 9 (**) | 81 (****) |
| Base + Tremor | 7 (**) | 132 (****) | 4 (*) | 1 (NS) |
| Base + Rigidity | 49 (****) | 211 (****) | 0 (NS) | 35 (****) |
| Base + Bradykinesia | 66 (****) | 389 (****) | 10 (**) | 58 (****) |
| Base + PIGD | 17 (****) | 321 (****) | 12 (***) | 73 (****) |
| Base + ADL | 88 (****) | NT | 9 (**) | 72 (****) |
| Base + MMSE | 8 (**) | 1 (NS) | NT | 0 (NS) |
| Base + HAM-D | 1 (NS) | 66 (****) | 1 (NS) | NT |
| Final Covariates | Time + age + UPDRS | Time + age + UPDRS | Age + PIGD | Time + UPDRS |
| Final + Selegiline@ | 13 (****) | 16 (****) | 4 (*) | 8 (*) |
| Final + Levodopa@ | 1 (NS) | 2 (NS) | 0 (NS) | 1 (NS) |
EOT, end of trial; UPDRS, United Parkinson's Disease Rating Scale; PIGD, postural instability gait disorder score; ADL, activities of daily living score; MMSE, minimum mental state examination score; HAM-D, Hamilton depression score; NT, not tested for inclusion.
#
Time since study entry (Gompertz hazard);
ξ
Age at study entry;
¥
Reference model is a constant-hazard model;
@
Reference model is the Final Covariates model;
&
On treatment is 1 and off-treatment is 0.
****
P value <= 0.0001;
***
P value <= 0.001;
**
P value <= 0.01;
*
P value <= 0.05. NS = not significant.