TABLE 1.
Patient Characteristics and Comorbidities in the Baseline Period
| Baseline Characteristicsa | High-Cost Patientsb (n = 1,859) | Lower-Cost Patientsb (n = 7,432) | P Valuec | ||
|---|---|---|---|---|---|
| N or Mean | % or SD | N or Mean | % or SD | ||
| Patient characteristics | |||||
| Age at index date | 42.5 | 13.9 | 36.1 | 14.4 | < 0.001 |
| Female | 819 | 55.9% | 4,244 | 42.9% | < 0.001 |
| U.S. Census divisiond | |||||
| East North Central | 368 | 19.8% | 1,427 | 19.2% | 0.561 |
| Middle Atlantic | 291 | 15.7% | 1,415 | 19.0% | < 0.001 |
| South Atlantic | 332 | 17.9% | 1,307 | 17.6% | 0.782 |
| West South Central | 230 | 12.4% | 736 | 9.9% | 0.002 |
| Mountain | 188 | 10.1% | 699 | 9.4% | 0.353 |
| Pacific | 188 | 10.1% | 575 | 7.7% | < 0.001 |
| East South Central | 89 | 4.8% | 596 | 8.0% | < 0.001 |
| West North Central | 106 | 5.7% | 344 | 4.6% | 0.054 |
| New England | 66 | 3.6% | 324 | 4.4% | 0.120 |
| Unknown | 1 | 0.1% | 9 | 0.1% | 0.698 |
| Year of index date | |||||
| 2006 | 228 | 12.3% | 860 | 11.6% | 0.406 |
| 2007 | 301 | 16.2% | 1,074 | 14.5% | 0.059 |
| 2008 | 262 | 14.1% | 1,145 | 15.4% | 0.158 |
| 2009 | 344 | 18.5% | 1,269 | 17.1% | 0.145 |
| 2010 | 413 | 22.2% | 1,669 | 22.5% | 0.824 |
| 2011 | 311 | 16.7% | 1,415 | 19.0% | 0.022 |
| Comorbidities | |||||
| Charlson Comorbidity Index | 0.8 | 1.4 | 0.2 | 0.7 | < 0.001 |
| Components of Charlson Comorbidity Index | |||||
| Chronic pulmonary disease | 240 | 12.9% | 417 | 5.6% | < 0.001 |
| Mild-to-moderate diabetes | 157 | 8.4% | 254 | 3.4% | < 0.001 |
| Rheumatologic disease | 94 | 5.1% | 93 | 1.3% | < 0.001 |
| Congestive heart failure | 95 | 5.1% | 72 | 1.0% | < 0.001 |
| Any malignancy including leukemia and lymphoma | 64 | 3.4% | 92 | 1.2% | < 0.001 |
| Cerebrovascular disease | 77 | 4.1% | 78 | 1.0% | < 0.001 |
| Diabetes with chronic complications | 62 | 3.3% | 65 | 0.9% | < 0.001 |
| Peripheral vascular disease | 54 | 2.9% | 68 | 0.9% | < 0.001 |
| Mild liver disease | 42 | 2.3% | 49 | 0.7% | < 0.001 |
| Renal disease | 50 | 2.7% | 32 | 0.4% | < 0.001 |
| Peptic ulcer disease | 26 | 1.4% | 26 | 0.3% | < 0.001 |
| Myocardial infarction | 21 | 1.1% | 17 | 0.2% | < 0.001 |
| Hemiplegia or paraplegia | 20 | 1.1% | 16 | 0.2% | < 0.001 |
| Metastatic solid tumor | 21 | 1.1% | 8 | 0.1% | < 0.001 |
| HIV/AIDS | 13 | 0.7% | 14 | 0.2% | < 0.001 |
| Moderate or severe liver disease | 8 | 0.4% | 5 | 0.1% | 0.001 |
| Dementia | 0 | 0.0% | 3 | 0.0% | 1.000 |
| Other selected comorbidities | |||||
| Nonopioid substance abuse diagnoses | 231 | 12.4% | 662 | 8.9% | < 0.001 |
| Psychotic disorders | 493 | 26.5% | 1,008 | 13.6% | < 0.001 |
| Other mental disorders | 672 | 36.1% | 1,900 | 25.6% | < 0.001 |
aThe baseline period was defined as the 6-month period prior to the 12-month observation period (which was centered on the index date).
bHigh-cost patients were defined as patients with health care costs in the top 20% of health care costs among all patients in the study cohort during the observation period.
cP values were calculated using chi-square tests for dichotomous variables and Wilcoxon rank-sum tests for continuous variables. Results were considered statistically significant at P<0.05.
dU.S. Census Bureau divisions were classified as follows: East North Central (IL, IN, MI, OH, WI); Middle Atlantic (NJ, NY, PA); South Atlantic (DC, DE, FL, GA, MD, NC, VA, SC, WV); West South Central (AR, LA, OK, TX); Mountain (AZ, CO, ID, MT, NM, NV, UT, WY); Pacific (AK, CA, HI, OR, WA); East South Central (AL, KY, MS, TN); West North Central (IA, KS, ND, MN, MO, NE, SD); and New England (CT, NH, MA, ME, RI, VT).
AIDS = acquired immune deficiency syndrome; HIV = human immunodeficiency virus; SD = standard deviation.