Table 2.
Demographics and Associations of Extreme Users of STM Tests and Radiographic Imaging
| STM Test | Radiographic Imaging | |||||||
|---|---|---|---|---|---|---|---|---|
| No. | % | OR* | 95% CI | No. | % | OR* | 95% CI | |
| No. of patients | 222 | 9.0 | 807 | 32.8 | ||||
| Age, years | ||||||||
| 65-69 | 66 | 29.7 | 0.98 | 0.68 to 1.42 | 232 | 28.7 | 1.07 | 0.84 to 1.37 |
| 70-74 | 75 | 33.8 | Reference | 239 | 29.6 | Reference | ||
| 75-79 | 48 | 21.6 | 0.84 | 0.56 to 1.25 | 182 | 22.6 | 0.99 | 0.77 to 1.28 |
| ≥ 80 | 33 | 14.9 | 0.57† | 0.37 to 0.90 | 154 | 19.1 | 0.67† | 0.52 to 0.87 |
| Diagnosis year | ||||||||
| 2002-2004 | 68 | 30.6 | Reference | 198 | 24.5 | Reference | ||
| 2005-2007 | 74 | 33.3 | 0.83 | 0.56 to 1.21 | 275 | 34.1 | 1.01 | 0.79 to 1.29 |
| 2008-2011 | 80 | 36.1 | 0.67† | 0.46 to 0.98 | 334 | 41.4 | 0.89 | 0.70 to 1.13 |
| Ethnicity | ||||||||
| White | 202 | 91.0 | Reference | 683 | 84.6 | Reference | ||
| Other/unknown | 20 | 9.0 | 0.69 | 0.42 to 1.14 | 124 | 15.4 | 1.11 | 0.85 to 1.45 |
| Marital status | ||||||||
| Married | 100 | 45.1 | Reference | 334 | 41.4 | Reference | ||
| Single | 112 | 50.4 | 0.80 | 0.59 to 1.08 | 437 | 54.1 | 0.76† | 0.63 to 0.93 |
| Geographic location | ||||||||
| Large metropolitan | 134 | 60.4 | 0.85 | 0.62 to 1.16 | 458 | 56.7 | 0.88 | 0.72 to 1.06 |
| Other | 88 | 39.6 | Reference | 349 | 43.3 | Reference | ||
| Charlson comorbidity score | ||||||||
| 0 | 142 | 64.0 | Reference | 447 | 55.5 | Reference | ||
| 1 | 52 | 23.4 | 1.00 | 0.70 to 1.42 | 204 | 25.3 | 1.19 | 0.96 to 1.48 |
| ≥ 2 | 28 | 12.6 | 0.87 | 0.56 to 1.36 | 155 | 19.2 | 1.61† | 1.25 to 2.08 |
| Region | ||||||||
| East | 70 | 31.5 | Reference | 237 | 29.4 | Reference | ||
| Midwest | 42 | 18.9 | 0.58† | 0.38 to 0.89 | 305 | 37.8 | 1.16 | 0.91 to 1.48 |
| West | 110 | 49.6 | 1.51† | 1.07 to 2.13 | 265 | 32.8 | 0.77† | 0.61 to 0.97 |
| Socioeconomic status | ||||||||
| Low | 71 | 32.0 | Reference | 382 | 47.4 | Reference | ||
| Medium | 67 | 30.2 | 1.53† | 1.05 to 2.23 | 184 | 22.9 | 0.84 | 0.66 to 1.06 |
| High | 84 | 37.8 | 1.56† | 1.07 to 2.27 | 239 | 29.7 | 0.98 | 0.77 to 1.24 |
| ER/PR status | ||||||||
| Positive | 174 | 77.0 | Reference | 557 | 69.0 | Reference | ||
| Negative | 23 | 10.2 | 0.59† | 0.37 to 0.95 | 159 | 19.7 | 1.93† | 1.50 to 2.49 |
| Unknown | 29 | 12.8 | 1.02 | 0.65 to 1.59 | 91 | 11.3 | 0.95 | 0.72 to 1.26 |
| PET use | ||||||||
| No | 53 | 23.9 | Reference | 208 | 25.8 | Reference | ||
| Yes | 169 | 76.1 | 2.02† | 1.42 to 2.88 | 599 | 74.2 | 2.77† | 2.26 to 3.39 |
| Maximum oncology office visit volume in any 1 year | ||||||||
| Low | 43 | 19.4 | Reference | 177 | 21.9 | Reference | ||
| Medium | 52 | 23.4 | 1.06 | 0.70 to 1.63 | 245 | 30.4 | 1.46† | 1.15 to 1.85 |
| High | 121 | 54.5 | 2.58† | 1.75 to 3.80 | 343 | 42.5 | 2.84† | 2.23 to 3.61 |
| Maximum No. of imaging tests in any 1 year | ||||||||
| ≤ 2 | 33 | 14.9 | Reference | |||||
| 3 | 32 | 14.4 | 0.95 | 0.57 to 1.59 | ||||
| 4 | 52 | 23.4 | 1.60 | 0.99 to 2.59 | ||||
| ≥ 5 | 105 | 47.3 | 1.72† | 1.10 to 2.68 | ||||
| More than 12 STM tests in any 1 year | 105 | 13.0 | ||||||
| No | 702 | 87.0 | Reference | |||||
| Yes | 105 | 13.0 | 1.44† | 1.06 to 1.96 | ||||
Abbreviations: ER/PR, estrogen receptor/progesterone receptor; OR, odds ratio; PET, positron emission tomography; STM, serum tumor marker.
*
ORs were derived from multivariable analysis, and models were adjusted for all other factors listed in the table.
*
P < .05.