Table 4.
Models of Observed Follow-Up and Second-Line Treatments
| Characteristic | Model 5 |
Model 6 |
||
|---|---|---|---|---|
| Effect | SE | Effect | SE | |
| Age | −0.00* | 0.000 | −0.00 | 0.003 |
| Female | −0.01 | 0.009 | 0.09 | 0.055 |
| First-line chemotherapy regimen, % | ||||
| FU (reference) | ||||
| IFL/FOLFIRI | −0.04† | 0.021 | 0.44* | 0.125 |
| IFL/FOLFIRI × postperiod cohort | −0.01 | 0.033 | 0.34‡ | 0.195 |
| FU/LV | 0.01 | 0.017 | −0.20‡ | 0.105 |
| FU/LV × postperiod cohort | −0.04‡ | 0.023 | 0.41* | 0.141 |
| FOLFOX | −0.01 | 0.016 | 0.30* | 0.097 |
| Other§ | −0.12† | 0.058 | −0.04 | 0.358 |
| Other biologic‖ | −0.12* | 0.041 | 0.95* | 0.240 |
| Capecitabine | −0.01 | 0.019 | 0.08 | 0.117 |
| Comorbid conditions | ||||
| Myocardial infarction | −0.02 | 0.029 | −0.17 | 0.176 |
| Congestive heart failure | 0.03‡ | 0.018 | −0.06 | 0.107 |
| Peripheral vascular disease | 0.02 | 0.022 | −0.03 | 0.136 |
| Cerebrovascular disease | 0.01 | 0.022 | 0.02 | 0.132 |
| Dementia | −0.11† | 0.048 | −0.01 | 0.291 |
| Chronic pulmonary disease | −0.00 | 0.014 | −0.11 | 0.088 |
| Ulcer | 0.01 | 0.032 | 0.21 | 0.192 |
| Mild liver disease | 0.02 | 0.043 | −0.45‡ | 0.272 |
| Diabetes | 0.02 | 0.013 | 0.12 | 0.079 |
| Diabetes with organ damage | 0.03 | 0.034 | 0.27 | 0.200 |
| Hemiplegia | 0.06 | 0.049 | −0.04 | 0.304 |
| Moderate/severe renal disease | 0.01 | 0.026 | −0.08 | 0.159 |
| Moderate/severe liver disease | −0.02 | 0.040 | −0.09 | 0.243 |
| AIDS | 0.03 | 0.084 | −0.22 | 0.543 |
| Rheumatologic disease | −0.01 | 0.045 | −0.09 | 0.280 |
| Resection | 0.06* | 0.010 | 0.78* | 0.059 |
| Observations | 5,874 | 5,874 | ||
NOTE. Second-line therapy is defined as chemotherapy 6 weeks to 3 months after initial treatment. All specifications include indicators for quarter of diagnosis. Model 5, observed follow-up days after diagnosis (Cox proportional hazard model); model 6, probability of second line treatment (logit). Data adapted from LifeLink Health Plans Claims Database.
Abbreviations: FU, fluorouracil; FOLFIRI, fluorouracil plus irinotecan; FOLFOX, fluorouracil/leucovorin with oxaliplatin; IFL, fluorouracil plus irinotecan; LV, leucovorin.
P < .01.
P < .05.
P < .1.
Capecitabine/oxaliplatin and capecitabine/irinotecan are included in Other category of first-line regimens.
FU/LV plus bevacizumab and IFL plus bevacuzimab are included in Other biologic category of first-line regimens.