Descriptive Analysis: Patient Demographics
Table 1 shows the total number of inpatient hospital admissions due to vertebral fracture and the rate per 10,000 women aged 50 and older in 1997. Overall, there were 53,066 acute inpatient hospital admissions for a primary diagnosis of osteoporotic vertebral fracture. Women aged 75 to 84 accounted for 42.7% of all admissions, while those aged 85 and older comprised another 34.2% of the total. In terms of incidence per 10,000 women, the rate increased with age, jumping substantially after age 74 from 8.6 per 10,000, among women aged 65 to 74, to 31.1 per 10,000 in those aged 75 to 84.
Table 1. Total inpatient hospital admissions for vertebral fractures and rate per 10,000 women in the United States, 1997
Table 2 provides results of mean charges and LOS according to patient age, race, location, primary payer, and source of admission. Hospital admissions for vertebral fractures in women aged 50 and older during 1997 resulted in a mean charge of $9532 (updated to year 2000) and a mean LOS of 6.2 days. More than 77% of all admissions were for patients aged 75 and older: 43% aged 75 to 84; 34% aged 85 or older. Mean charges decreased with age, falling from $13,073 among 50- to 64-year-olds to $8,132 for those 85 or older. Mean charge values for all age groups were significantly different from the highest mean for the 50- to 64-year-old group. Mean LOS decreased with age from 6.5 days to 6.1 days, although there were no statistically significant differences across age groups.
Table 2. Demographic stratification of mean acute/inpatient hospital charges and length of stay for vertebral fracture cases in the United States
| 65–74||8,665||10,994||319||†||6.2||0.12|| |
| 75–84||22,877||9,613||217||†||6.3||0.11|| |
| 85+||18,362||8,132||180||†||6.1||0.18|| |
| Hispanic||1,222||13,967||1017||†||7.2||0.46|| |
| Other§||750||11,318||1286|| ||7.0||1.09|| |
| West||9,707||10,987||354|| ||6.3||0.33||†|
| Other||369||8,072||763|| ||4.6||0.34||†|
| Emergency||29,488||9,192||212|| ||5.7||0.10||†|
| Other hospital||3,079||13,705||686||†||12.3||0.48||†|
| Other facility||1,014||10,809||779|| ||6.4||0.34|
Within the race stratum of those with an identifiable race, white patients accounted for the majority of cases (93.7%), followed by Hispanic patients (2.9%) and black patients (1.6%). Patients of various less common racial origin were combined in a single category: other. Mean charges were significantly higher among black patients ($17,118) and Hispanic patients ($13,967) compared to the reference group of white women ($9469). Mean LOS was highest for black patients (8.9 days) and was significantly different from white patients (6.4 days).
Among regions, the highest charges and longest LOS were in the Northeast ($11,661 and 8.2 days). Difference in mean charges and LOS between the Northeast and the other three regions all reached statistical significance, except when compared to charges for the West. Patients in the Midwest had the lowest mean charges ($7852), while LOS was shortest (5.5 days) in the South.
About 89% of patients admitted to a hospital for osteoporotic vertebral fractures reported Medicare as the primary payer. Medicaid patients incurred the highest mean charges: $16,115; self-pay patients, $14,864; patients covered by commercial payers, $10,394; Medicare patients, $9,316. Self-pay patients, by definition, are not covered by third-party insurance and cannot command volume or other contractual discounts from hospitals. Thus they are usually billed for higher totals for the same care when compared to patients with private or government health insurance. Compared to Medicare, differences in mean charges for these payers were statistically significant. Differences in mean LOS were also statistically significant for Medicaid (7.6 days) and commercial payers (5.5 days) when compared with Medicare (6.2 days).
The source designation for a majority of patients (55%) was emergency, followed by routine admission (32%). Patients admitted from “other hospitals” (i.e., transferred from another, usually acute-care, hospital) had statistically, significantly higher charges (about 30%) compared to routine admissions ($13,705 vs. $9,643). LOS was significantly longer for other hospital transfer cases compared to routine cases (12.3 vs. 6.1 days), while emergency patients had statistically significant and slightly shorter stays in the unadjusted analysis. Both the higher charges and longer LOS in cases transferred from other hospitals may reflect the greater severity of these fractures, as the hospital of origin may not have had the necessary intensive care resources to treat these patients.
Results from the logistic regression models predicting discharges to post-acute care are shown in Table 3. More than 40% of all hospital patients with osteoporosis-related vertebral fractures were discharged to a LTC facility, 1.7% to a different STAC hospital, 9.5% to another type of facility, and 13.1% were discharged with HHC. Thus, nearly 65% of these patients were discharged to one of the four post-acute care settings. The proportion of vertebral fracture patients discharged to a LTC facility increased dramatically with age, rising from 12% in women aged 50 to 64 to more than 51% in those aged 85 or older. An analysis of the odds ratios for each age group compared to the 50- to 64-year-old group reinforces this rising trend toward more LTC. Women 65 to 74 years of age are approximately 2.9 times more likely to be discharged to a LTC facility compared to those aged between 50 and 64 years, while women 75 to 84 years old and those 85 years and older are nearly 5.0 and 7.9 times more likely to receive post-acute care in a LTC facility, respectively. Discharge to another STAC hospital was most frequent among 50- to 64-year-olds (3.1%), while the highest proportion of patients discharged to an “other” facility (10.1%) and to HHC (14.4%) was found among those 85 or older and among 75- to 84-year-olds, respectively. Also, the use of any type of post-acute care increased with age: 35% for those aged 50 to 64; 53% for those aged 65 to 74; 66% for patients aged 75 to 84, and 74% in patients 85 and older.
Table 3. Discharge disposition for vertebral fracture hospital cases in the United States by demographic strata
|Total||53,066||40.4||—|| ||1.7||—|| ||9.5||—|| ||13.1||—|| ||33.7||—|| |
| 50–64‡||3,161||12.0||—|| ||3.1||—|| ||6.8||—|| ||12.7||—|| ||61.7||—|| |
| 65–74||8,665||28.1||2.87||†||2.7||0.85|| ||8.4||1.27|| ||14.3||1.15|| ||44.7||0.50||†|
| 75–84||22,877||40.3||4.97||†||1.2||0.39||†||9.9||1.51||†||14.4||1.16|| ||32.7||0.30||†|
| 85+||18,362||51.7||7.89||†||1.4||0.46||†||10.1||1.55||†||10.8||0.84|| ||25.0||0.21||†|
| White‡||40,031||42.2||—|| ||1.7||—|| ||9.5||—|| ||12.8||—|| ||32.6||—|| |
| Black||699||20.9||0.36||†||4.5||2.80||†||14.1||1.56|| ||12.0||0.93|| ||42.7||1.54||†|
| Hispanic||1,222||22.0||0.39||†||2.4||1.46|| ||14.1||1.57|| ||17.4||1.43|| ||39.7||1.36||†|
| Other§||750||25.7||0.47||†||2.5||1.55|| ||8.9||0.93|| ||10.6||0.80|| ||44.2||1.64||†|
| Northeast‡||11,019||36.4||—|| ||1.3||—|| ||10.2||—|| ||11.3||—|| ||39.3||—|| |
| Midwest||15,857||46.8||1.53||†||1.9||1.51|| ||6.6||0.62||†||11.5||1.02|| ||32.1||0.73||†|
| South||16,483||37.0||1.02|| ||1.7||1.33|| ||11.9||1.18|| ||14.0||1.28||†||34.7||0.82|| |
| West||9,707||—||—|| ||1.6||1.26|| || ||—|| ||16.1||1.50||†||28.3||0.61|| |
| Medicare‡||47,078||42.3||—|| ||1.6||—|| ||9.8||—|| ||13.1||—|| ||31.6||—|| |
| Medicaid||787||15.3||0.25||†||1.9||1.19|| ||7.8||0.77|| ||15.6||1.22|| ||54.4||2.59||†|
| Commercial||4,440||26.4||0.49||†||1.6||1.01|| ||6.5||0.64||†||12.1||0.91|| ||48.5||2.04||†|
| Self-pay||346||11.7||0.18||†||4.0||2.85||†||4.7||0.45||†||13.9||1.07|| ||61.3||3.43||†|
| Other||369||16.1||0.26||†||4.5||3.53||†||7.9||0.78|| ||11.9||0.89|| ||59.9||3.24||†|
| Emergency||29,488||43.0||1.35||†||1.2||0.67||†||10.3||1.13|| ||12.5||0.95|| ||30.7||0.73||†|
| Other hosp.||3,079||21.3||0.48||†||5.4||3.20||†||7.0||0.74|| ||28.3||2.64||†||39.9||1.10|| |
| Other fac.||1,014||54.7||2.17||†||1.4||0.79|| ||9.6||1.04|| ||10.3||0.77|| ||20.9||0.44||†|
| Routine‡||16,948||35.8||—|| ||1.8||—|| ||9.2||—|| ||13.0||—|| ||37.6||—|| |
In terms of the race stratum, white patients were most frequently discharged to LTC. Patients of other races were significantly less likely to be discharged to a LTC facility compared to white patients, ranging from about one-third (black) to one-half (other) as likely. The proportion of patients discharged to other types of post-acute care were generally higher in black and Hispanic patients versus white patients, although statistically significant differences in discharge destinations existed only for black patients discharged to STAC compared to the reference group (4.5% vs. 1.7%; OR = 2.80).
Patients from the Midwest were discharged in highest proportion to LTC, and patients there were about 53% more likely to be discharged to a LTC facility than patients in the Northeast (46.8% vs. 36.4%; OR = 1.53). The opposite was found for patients discharged to other facilities, as Midwest patients had the lowest proportion (6.6%) and were least likely to be discharged to other facilities (OR = 0.62). Discharge proportions for HHC ranged from 11.3% in the Northeast to 16.1% in the West, and patients in the West were 50% more likely to receive HHC upon discharge compared to patients in the Northeast (OR = 1.5). The highest proportion of patients to be discharged to one of the four types of post-acute care were from the Midwest (66.8%) followed by patients from the South (64.6%), and those least likely to receive post-acute care were from the Northeast (59.2%).
Medicare patients were discharged in highest proportion to LTC (42.3%), while Medicaid and self-pay patients were least likely to be discharged to LTC (15.3% and 11.7%). Compared to Medicare patients, patients of all other payer types were less frequently discharged to LTC, with statistically significant odds ratios that ranged from 0.18 to 0.49. The proportion of patients being discharged to any type of post-acute care ranged from a high of 66.8% (Medicare) to a low of 34.3% (self-pay).
The distribution of post-acute care discharges by admission source shows that patients admitted to acute care hospitals from other facilities (e.g. skilled nursing facilities) were greater than two times more likely to be discharged to a LTC facility versus patients considered as routine admissions. Almost 80% of the patients admitted from another facility were discharged to some form of post-acute care. Patients admitted from another acute-care facility were discharged in lowest proportions to a LTC facility, but were those most frequently discharged to another STAC facility (5.4%), to home with HHC (28.3%), or as a routine discharge (39.9%).
Descriptive Analysis: Hospital Characteristics
Table 4 presents results by several hospital stratifications. Results according to hospital location indicate that nearly 23% of vertebral fractures were in rural hospitals and 77% were in urban hospitals. Mean charges and LOS were significantly lower in rural hospitals ($6,053 vs. $10,562; 5.4 days vs. 6.5 days). Approximately 76% of all cases were in non-teaching hospitals. Mean charges and LOS were lower in non-teaching than in teaching hospitals ($8,786 vs. $11,975; and 6.0 days vs. 7.0 days).
Table 4. Mean charges and length of stay for vertebral fracture hospital cases in the United States by hospital location, teaching status, bed size, and ownership type
| Rural|| || || || || || || |
| Small (1–49)||3,206||4,490||117||†||4.8||0.15||†|
| Medium (50–99)||4,061||6,142||439|| ||5.3||0.18||†|
| Large (100+)‡||4,982||6,979||225||—||5.9||0.25||—|
| Small (1–99)||3,408||9,123||734|| ||6.9||0.55|| |
| Medium (100–199)||9,417||9,805||366|| ||6.4||0.27|| |
| Large (200+)‡||15,679||10,204||309||—||6.1||0.12||—|
| Small (1–299)||3,380||11,163||761|| ||6.4||0.44|| |
| Medium (300–499)||4,546||11,379||828|| ||6.6||0.63|| |
| Large (500+)‡||4,311||13,311||1049||—||7.7||0.39||—|
| Government||6,402||8,226||405||†||6.0||0.21|| |
| Private nonprofit‡||38,929||9,638||220||—||6.3||0.12||—|
| Private for-profit||7,660||10,092||375|| ||5.8||0.32|| |
For patients treated in rural hospitals, the number of cases, mean charges, and mean LOS all increased with hospital bed size. Mean charges and LOS in small hospitals were lower compared with those in the largest rural hospitals ($4,490 vs. $6,979; 4.8 vs. 5.9). In urban non-teaching hospitals, mean charges and LOS ranged from $9123 to $10,204 and 6.1 to 6.9 days, respectively, but no statistically significant differences were found in comparison to the reference group (large urban non-teaching). Charges and LOS were the highest for urban teaching hospitals among all hospital strata. However, within the urban teaching category, there were no statistically significant differences in means.
Results by ownership control show that more than 73% of all vertebral fractures were treated in private, nonprofit hospitals, while the remainder was split between government (12%) and private, for-profit hospitals (15%). Mean charges were highest in private, for-profit hospitals ($10,092) and lowest in government-controlled hospitals ($8,226). Mean charges in private nonprofit hospitals were $9638 and differed significantly compared to mean charges in government hospitals.
Table 5 presents results regarding discharges to post-acute care according to key hospital characteristics. Among urban and rural hospitals, the proportions for each of the four types of post- acute care were statistically significantly different. Rural hospitals discharged a greater proportion of patients to LTC (43.1% vs. 39.5%, OR = 1.16) and to STAC hospitals (2.7% vs. 1.3%, OR = 2.03), while urban hospitals discharged the highest proportion of patients to other facilities (10.6% vs. 6.4%, OR = 0.58) and to HHC (13.9% vs. 10.2%, OR = 0.7). The total overall proportion of patients discharged to post-acute care was greater in urban hospitals (65.3% vs. 62.4%).
Table 5. Discharge disposition for vertebral fracture hospital cases in the United States by location, teaching status, bed size, and ownership type
|Total||53,066||40.4||—|| ||1.7||—|| ||9.5||—|| ||13.1||—|| ||33.7||—|| |
| Urban‡||40,742||39.5||—|| ||1.3||—|| ||10.6||—|| ||13.9||—|| ||32.7||—|| |
| Non-teaching‡||40,658||41.0||—|| ||1.9||—|| ||8.9||—|| ||12.6||—|| ||34.2||—|| |
| Teaching||12,334||38.7||0.91|| ||0.9||0.49||†||11.5||1.32||†||14.5||1.17|| ||32.1||0.91|| |
|Rural|| || || || || || || || || || || || || || || || |
| Small (1–49)||3,206||48.7||1.46||†||4.0||1.83||†||2.7||0.26||†||5.7||0.49||†||39.4||1.16|| |
| Medium (50–99)||4,061||43.5||1.18|| ||2.2||0.98|| ||5.1||0.51||†||12.7||1.18|| ||36.2||1.01|| |
| Large (100+)‡||4,982||39.5||—|| ||2.2||—|| ||9.6||—|| ||11.0||—|| ||35.9||—|| |
| Small (1–99)||3,408||40.7||1.04|| ||1.9||2.22||†||4.0||0.33||†||10.6||0.68||†||41.5||1.55||†|
| Medium (100–199)||9,417||40.0||1.01|| ||2.5||2.95||†||10.7||0.95|| ||13.0||0.86|| ||32.7||1.06|| |
| Large (200+)‡||15,679||39.8||—|| ||0.9||—|| ||11.2||—|| ||14.8||—|| ||31.4||—|| |
| Small (1–299)||3,380||43.1||1.45|| ||1.1||0.70|| ||10.2||0.84|| ||13.9||0.94|| ||30.2||0.78|| |
| Medium (300–499)||4,546||40.2||1.29|| ||0.3||0.19|| ||12.3||1.03|| ||15.1||1.04|| ||30.0||0.77|| |
| Large (500+)‡||4,311||34.3||—|| ||1.5||—|| ||11.9||—|| ||14.6||—|| ||35.6||—|| |
| Private nonprofit‡||38,929||41.7||—|| ||1.4||—|| ||10.2||—|| ||13.3||—|| ||31.7||—|| |
| Private for-profit||7,660||36.0||0.79||†||1.8||1.25|| ||9.9||0.97|| ||15.6||1.21||†||36.3||1.23|| |
In terms of teaching status, the proportion of patients discharged to any type of post-acute care was about 65% in both types of hospitals, although a higher proportion of non-teaching hospital cases were discharged to a STAC hospital, while a larger percentage of teaching hospital patients were discharged to an “other” facility.
The analysis by hospital according to bed size revealed that smaller rural hospitals discharged a higher proportion of patients to LTC (48.7% vs. 39.5%; OR = 1.46) and STAC (4% vs. 2.2%; OR = 1.83) and lower proportions to other facilities (2.7% vs. 9.6%; OR = 0.26) and HHC (5.7% vs. 11%; OR = 0.49). Among urban hospitals, similar patterns were found whereby higher proportions of patients were discharged to LTC from smaller hospitals compared to large hospitals, while the inverse was true for the proportion of patients discharged to other facilities and to HHC.
Compared to government and private for-profit hospitals, private nonprofit hospitals discharged a greater percentage of patients to LTC (41.7%) and to other facilities (10.2%). Government hospitals discharged the highest proportion of patients to STAC hospitals (3.0%) while private for-profit hospitals discharged 15.6% of patients to HHC (OR = 1.21, p < .05). Almost 55% of all cases from government hospitals received some type of post-acute care, whereas more than 66% of cases from private, nonprofit hospitals received such care.
Multivariate Regression Results
The coefficients and standard errors from the log of charges and the log of LOS multivariate regression models are presented in Table 6. Most of the percentage effects on charges and LOS were smaller in the multivariate analysis than in the unadjusted analysis. In terms of age, patients 85 and older incurred charges 24% lower than those aged 50 to 64, after semi-logarithmic transformations were applied [14,15], while the unadjusted analysis (Table 1) revealed mean charges that were 61% lower. Results according to patients’ race indicate that Hispanic patients had significantly higher charges than white patients, but mean charges were not statistically different when black patients were compared to white patients when all other factors were held constant. In terms of payer type, commercial patients and “other” paying patients incurred lower mean charges compared to Medicare patients, and Medicaid patients had statistically significantly higher charges. The effect of commercial payer status switched from being about 10% above Medicare in the unadjusted, descriptive analysis to about 15% lower in the multivariate analysis. After controlling for all other factors, there was a large and significant impact on charges from patients admitted from another acute-care hospital versus those considered to be routine admissions. However, the relative impact on charges of being admitted from another acute-care hospital was attenuated in the multivariate analysis compared to the descriptive analysis (42% versus 35% higher). Finally, the effect on charges of being in a private for-profit hospital versus a private nonprofit setting, became statistically significant, while the statistically significant difference with government controlled hospitals was lost in the multivariate regression estimation.
Table 6. Regression results from total charge and length-of-stay models (log form)
| 50–64|| || || || || || |
| 75–84||−0.17||*||0.04||−0.04|| ||0.04|
| White|| || || || || || |
| Black||0.10|| ||0.08||0.03|| ||0.07|
| Hispanic||0.19||*||0.04||0.09|| ||0.05|
| Asian/Pac Islander||–0.001|| ||0.07||0.01|| ||0.08|
| Northeast|| || || || || || |
| West||−0.001|| ||0.05||−0.35||*||0.04|
| Medicare|| || || || || || |
| Medicaid||0.12||*||0.06||0.11|| ||0.06|
| Commercial||−0.16||*||0.04||−0.19|| ||0.03|
| Self-pay||−0.07|| ||0.11||0.06|| ||0.10|
| Routine|| || || || || || |
| Emergency dept||–0.01|| ||0.02||−0.05||*||0.02|
| Another hosp.||0.30||*||0.05||0.78||*||0.04|
| Other facility||0.02|| ||0.06||0.00|| ||0.06|
| Urban|| || || || || || |
| Rural||−0.33||*||0.03||−0.05|| ||0.03|
| Non-teaching|| || || || || || |
| Large|| || || || || || |
| Private nonprofit|| || || || || || |
| Government||0.04|| ||0.03||0.02|| ||0.03|
| Private for-profit||0.14||*||0.03||−0.05|| ||0.03|
|Number of obs.||40,021|| || ||40,116|| || |
|R-square||0.136|| || ||0.133|| || |
The magnitude of the coefficients in the LOS regression analysis was generally reduced compared to the descriptive analysis. However, the coefficient on admission source from another acute hospital was highly significant and the percentage effect more than doubled compared to the unadjusted analysis. The simultaneous control of patient demographics and hospital characteristics resulted in some variables becoming statistically significant (e.g. AGE = 65–74, 85+) or losing statistical significance (RACE = black; PAYER = Medicaid, Commercial; LOCATION = rural; OWNERSHIP = government).