Table 4.
Multilevel regression models for percentage of comorbidities over time.
| Coefficient (SE) | P value | |
|---|---|---|
| Model 1: Unadjusted multilevel model for percentage of comorbidities over timea | ||
| Start year | −0.19 (0.24) | 0.439 |
| Study duration | −0.28 (0.39) | 0.466 |
| Constant | 38.74*** (5.92) | 0.000 |
| Model 2: Multilevel model for percentage of comorbidities over time adjusted for tumor typesb | ||
| Tumor type | ||
| Multipled | (baseline) | |
| Melanoma | −6.50 (9.70) | 0.502 |
| Prostate | −8.73 (7.16) | 0.223 |
| Lung | 13.21 (7.39) | 0.074 |
| Breast | −12.65 (7.34) | 0.085 |
| Colorectal | 1.28 (7.39) | 0.863 |
| Start year | −0.21 (0.20) | 0.304 |
| Study duration | −0.21 (0.33) | 0.519 |
| Constant | 41.99*** (8.37) | 0.000 |
| Model 3: Multilevel model for percentage of comorbidities adjusted for all determinantsc | ||
| Country | ||
| Australia | (baseline) | |
| Canada | −3.25 (4.29) | 0.448 |
| Denmark | 18.30*** (5.17) | 0.000 |
| France | 0.64 (12.12) | 0.958 |
| Italy | 4.60 (11.78) | 0.696 |
| Japan | −18.98 (11.33) | 0.094 |
| The Netherlands | 31.40*** (5.84) | 0.000 |
| New Zealand | 5.61 (8.55) | 0.512 |
| Norway | −1.88 (4.45) | 0.673 |
| Spain | 12.94 (10.98) | 0.238 |
| Sweden | 16.05** (5.42) | 0.003 |
| UK | 5.81 (3.88) | 0.134 |
| USA | 11.13** (4.28) | 0.009 |
| Data type | ||
| Hospital-based routinely collected data | (baseline) | |
| Claims data | 11.62*** (2.58) | 0.000 |
| Other/unknown | 9.16 (9.22) | 0.320 |
| Tumor type | ||
| Multipled | (baseline) | |
| Breast | 3.93 (6.5) | 0.545 |
| Lung | 12.96* (5.47) | 0.018 |
| Prostate | −19.64** (6.24) | 0.002 |
| Colorectal | 3.87 (5.49) | 0.481 |
| Melanoma | −4.24 (7.03) | 0.547 |
| Metastatic | ||
| No distinction | (baseline) | |
| Metastasis only | 0.9 (2.02) | 0.657 |
| Metastasis excluded | 1.57 (2.64) | 0.553 |
| Index category | ||
| Charlson comorbidity index | (baseline) | |
| Elixhauser comorbidity index | 14.95*** (2.68) | 0.000 |
| C3 index | 18.27*** (5.54) | 0.001 |
| Other | −5.19 (5.85) | 0.374 |
| Age groupe | ||
| Age below 45 | −5.77* (2.41) | 0.017 |
| Age 45–59 | −1.83 (2.52) | 0.467 |
| Age 60–69 | 0.32 (2.54) | 0.899 |
| Age 70–79 | 5.26 (2.79) | 0.059 |
| Age 80 or above | 8.94*** (2.78) | 0.001 |
| Presence of subtype | ||
| No | (baseline) | |
| Yes | 1.56 (1.98) | 0.429 |
| Proportion male | 29.43*** (7.37) | 0.000 |
| Reporting quality | ||
| Valid | (baseline) | |
| Not valid | 4.76 (4.11) | 0.247 |
| Validity score | 1.75 (1.23) | 0.154 |
| Start year | 0.54** (0.18) | 0.004 |
| Study duration | 0.10 (0.31) | 0.740 |
| Constant | −26.11* (12.07) | 0.030 |
Note: Significant: *, P < 0.05; **, P < 0.01; ***, P < 0.001.
aObservations = 208, number of groups = 140, log likelihood = −869.06.
bObservations = 208, number of groups = 140, log likelihood = −822.30.
cObservations = 199, number of groups = 137, log likelihood = −721.43.
dThe category multiple includes observations that make no distinction between the tumor types and can therefore not be presented within the categories of the individual tumor types.
eObservations can be classified into multiple age groups (e.g., studies that include ages 60–80 are included in age groups 60–69 and 70–79). The observations by age are thus not mutually exclusive. Therefore, dummy variables were entered in the model per category.