Defining emergency department episodes by severity and intensity: A 15-year study of Medicare beneficiaries.

BACKGROUND: Episodes of Emergency Department (ED) service use among older adults previously have not been constructed, or evaluated as multi-dimensional phenomena. In this study, we constructed episodes of ED service use among a cohort of older adults over a 15-year observation period, measured the episodes by severity and intensity, and compared these measures in predicting subsequent hospitalization. METHODS: We conducted a secondary analysis of the prospective cohort study entitled the Survey on Assets and Health Dynamics among the Oldest Old (AHEAD). Baseline (1993) data on 5,511 self-respondents >or=70 years old were linked to their Medicare claims for 1991-2005. Claims then were organized into episodes of ED care according to Medicare guidelines. The severity of ED episodes was measured with a modified-NYU algorithm using ICD9-CM diagnoses, and the intensity of the episodes was measured using CPT codes. Measures were evaluated against subsequent hospitalization to estimate comparative predictive validity. RESULTS: Over 15 years, three-fourths (4,171) of the 5,511 AHEAD participants had at least 1 ED episode, with a mean of 4.5 episodes. Cross-classification indicated the modified-NYU severity measure and the CPT-based intensity measure captured different aspects of ED episodes (kappa = 0.18). While both measures were significant independent predictors of hospital admission from ED episodes, the CPT measure had substantially higher predictive validity than the modified-NYU measure (AORs 5.70 vs. 3.31; p < .001). CONCLUSIONS: We demonstrated an innovative approach for how claims data can be used to construct episodes of ED care among a sample of older adults. We also determined that the modified-NYU measure of severity and the CPT measure of intensity tap different aspects of ED episodes, and that both measures were predictive of subsequent hospitalization.

The aftermath of hip fracture: discharge placement, functional status change, and mortality.

The authors prospectively explored the consequences of hip fracture with regard to discharge placement, functional status, and mortality using the Survey on Assets and Health Dynamics Among the Oldest Old (AHEAD). Data from baseline (1993) AHEAD interviews and biennial follow-up interviews were linked to Medicare claims data from 1993-2005. There were 495 postbaseline hip fractures among 5,511 respondents aged >or=69 years. Mean age at hip fracture was 85 years; 73% of fracture patients were white women, 45% had pertrochanteric fractures, and 55% underwent surgical pinning. Most patients (58%) were discharged to a nursing facility, with 14% being discharged to their homes. In-hospital, 6-month, and 1-year mortality were 2.7%, 19%, and 26%, respectively. Declines in functional-status-scale scores ranged from 29% on the fine motor skills scale to 56% on the mobility index. Mean scale score declines were 1.9 for activities of daily living, 1.7 for instrumental activities of daily living, and 2.2 for depressive symptoms; scores on mobility, large muscle, gross motor, and cognitive status scales worsened by 2.3, 1.6, 2.2, and 2.5 points, respectively. Hip fracture characteristics, socioeconomic status, and year of fracture were significantly associated with discharge placement. Sex, age, dementia, and frailty were significantly associated with mortality. This is one of the few studies to prospectively capture these declines in functional status after hip fracture.

A 12-year prospective study of stroke risk in older Medicare beneficiaries.

BACKGROUND: 5.8 M living Americans have experienced a stroke at some time in their lives, 780K had either their first or a recurrent stroke this year, and 150K died from strokes this year. Stroke costs about $66B annually in the US, and also results in serious, long-term disability. Therefore, it is prudent to identify all possible risk factors and their effects so that appropriate intervention points may be targeted. METHODS: Baseline (1993-1994) interview data from the nationally representative Survey on Assets and Health Dynamics among the Oldest Old (AHEAD) were linked to 1993-2005 Medicare claims. Participants were 5,511 self-respondents >or= 70 years old. Two ICD9-CM case-identification approaches were used. Two approaches to stroke case-identification based on ICD9-CM codes were used, one emphasized sensitivity and the other emphasized specificity. Participants were censored at death or enrollment into managed Medicare. Baseline risk factors included sociodemographic, socioeconomic, place of residence, health behavior, disease history, and functional and cognitive status measures. A time-dependent marker reflecting post-baseline non-stroke hospitalizations was included to reflect health shocks, and sensitivity analyses were conducted to identify its peak effect. Competing risk, proportional hazards regression was used. RESULTS: Post-baseline strokes occurred for 545 (9.9%; high sensitivity approach) and 374 (6.8%; high specificity approach) participants. The greatest static risks involved increased age, being widowed or never married, living in multi-story buildings, reporting a baseline history of diabetes, hypertension, or stroke, and reporting difficulty picking up a dime, refusing to answer the delayed word recall test, or having poor cognition. Risks were similar for both case-identification approaches and for recurrent and first-ever vs. only first-ever strokes. The time-dependent health shock (recent hospitalization) marker did not alter the static model effect estimates, but increased stroke risk by 200% or more. CONCLUSION: The effect of our health shock marker (a time-dependent recent hospitalization indicator) was large and did not mediate the effects of the traditional risk factors. This suggests an especially vulnerable post-hospital transition period from adverse effects associated with both their underlying health shock (the reasons for the recent hospital admission) and the consequences of their treatments.

Emergency department utilization patterns among older adults.

BACKGROUND: We identified 4-year (2 years before and 2 years after the index [baseline] interview) ED use patterns in older adults and the factors associated with them. METHODS: A secondary analysis of baseline interview data from the nationally representative Survey on Assets and Health Dynamics Among the Oldest Old linked to Medicare claims data. Participants were 4310 self-respondents 70 years old or older. Current Procedural Terminology (CPT) codes 99281 and 99282 identified low-intensity use, and CPT codes 99283-99285 identified high-intensity use. Exploratory factor analysis and multivariable multinomial logistic regression were used. RESULTS: The majority (56.6%) of participants had no ED visits during the 4-year period. Just 5.7% had only low-intensity ED use patterns, whereas 28.9% used the ED only for high-intensity visits, and 8.7% had a mixture of low-intensity and high-intensity use. Participants with lower immediate word recall scores and those who did not live in major metropolitan areas were more likely to be low-intensity-only ED users. Older individuals, those who did not live in rural counties, had greater morbidity and functional status burdens, and lower immediate word recall scores were more likely to be high-intensity-only ED users. Participants who were older, did not live in major cities, had lower education levels, had greater morbidity and functional status burdens, and lower immediate word recall scores were more likely to have mixed ED use patterns. CONCLUSIONS: Nearly half of these older adults used the ED at least once over a 4-year period, with a mean annual ED use percentage of 18.4. Few, however, used the ED only for visits that may have been avoidable. This finding suggests that triaging Medicare patients would not decrease ED overcrowding, although continued surveillance is necessary to detect potential changes in ED use patterns among older adults.

An interpersonal continuity of care measure for Medicare Part B claims analyses.

OBJECTIVES: This article presents an interpersonal continuity of care measure. METHODS: We operationalized continuity of care as no more than an 8-month interval between any two visits during a 2-year period to either (a) the same primary care physician or (b) the same physician regardless of specialty. Sensitivity analyses evaluated two interval censoring algorithms and two alternative intervals. We linked Medicare Part A and B claims to baseline survey data for 4,596 respondents to the Survey on Asset and Health Dynamics Among the Oldest Old. We addressed the potential for selection bias by using propensity score methods, and we explored construct validity. RESULTS: Interpersonal continuity with a primary care physician was 17.3%, and interpersonal continuity of care with any physician was 26.1%. Older participants; men; individuals who lived alone; people who had difficulty walking; and respondents with medical histories of arthritis, cancer, diabetes, heart conditions, hypertension, and stroke were most likely to have continuity. Individuals who had never married, were widowed, were working, or had low subjective life expectancy were least likely to have continuity. DISCUSSION: Researchers can measure interpersonal continuity of care using Medicare Part B claims. Replication of these findings and further construct validation, however, are needed prior to widespread adoption of this method.

The use of chiropractors by older adults in the United States.

BACKGROUND: In a nationally representative sample of United States Medicare beneficiaries, we examined the extent of chiropractic use, factors associated with seeing a chiropractor, and predictors of the volume of chiropractic use among those having seen one. METHODS: We performed secondary analyses of baseline interview data on 4,310 self-respondents who were 70 years old or older when they first participated in the Survey on Assets and Health Dynamics Among the Oldest Old (AHEAD). The interview data were then linked to their Medicare claims. Multiple logistic and negative binomial regressions were used. RESULTS: The average annual rate of chiropractic use was 4.6%. During the four-year period (two years before and two years after each respondent's baseline interview), 10.3% had one or more visits to a chiropractor. African Americans and Hispanics, as well as those with multiple depressive symptoms and those who lived in counties with lower than average supplies of chiropractors were much less likely to use them. The use of chiropractors was much more likely among those who drank alcohol, had arthritis, reported pain, and were able to drive. Chiropractic services did not substitute for physician visits. Among those who had seen a chiropractor, the volume of chiropractic visits was lower for those who lived alone, had lower incomes, and poorer cognitive abilities, while it was greater for the overweight and those with lower body limitations. CONCLUSION: Chiropractic use among older adults is less prevalent than has been consistently reported for the United States as a whole, and is most common among Whites, those reporting pain, and those with geographic, financial, and transportation access.

Prior hospitalization and the risk of heart attack in older adults: a 12-year prospective study of Medicare beneficiaries.

BACKGROUND: We investigated whether prior hospitalization was a risk factor for heart attacks among older adults in the survey on Assets and Health Dynamics among the Oldest Old. METHODS: Baseline (1993-1994) interview data were linked to 1993-2005 Medicare claims for 5,511 self-respondents aged 70 years and older and not enrolled in managed Medicare. Primary hospital International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) 410.xx discharge codes identified postbaseline hospitalizations for acute myocardial infarctions (AMIs). Participants were censored at death or postbaseline managed Medicare enrollment. Traditional risk factors and other covariates were included. Recent postbaseline non-AMI hospitalizations (ie, prior hospitalizations) were indicated by a time-dependent marker, and sensitivity analyses identified their peak effect. RESULTS: The total number of person-years of surveillance was 44,740 with a mean of 8.1 (median = 9.1) per person. Overall, 483 participants (8.8%) suffered postbaseline heart attacks, with 423 participants (7.7%) having their first-ever AMI. As expected, significant traditional risk factors were sex (men); race (whites); marital status (never being married); education (noncollege); geography (living in the South); and reporting a baseline history of angina, arthritis, diabetes, and heart disease. Risk factors were similar for both any postbaseline and first-ever postbaseline AMI analyses. The time-dependent recent non-AMI hospitalization marker did not alter the effects of the traditional risk factors but increased AMI risk by 366% (adjusted hazards ratio = 4.66, p < .0001). Discussion. Our results suggest that some small percentage (<3%) of heart attacks among older adults might be prevented if effective short-term postdischarge planning and monitoring interventions were developed and implemented.

Continuity of care with a primary care physician and mortality in older adults.

BACKGROUND: We examined whether older adults who had continuity of care with a primary care physician (PCP) had lower mortality. METHODS: Secondary analyses were conducted using baseline interview data (1993-1994) from the nationally representative Survey on Assets and Health Dynamics among the Oldest Old (AHEAD). The analytic sample included 5,457 self-respondents 70 years old or more who were not enrolled in managed care plans. AHEAD data were linked to Medicare claims for 1991-2005, providing up to 12 years of follow-up. Two time-dependent measures of continuity addressed whether there was more than an 8-month interval between any two visits to the same PCP during the prior 2-year period. The "present exposure" measure calculated this criterion on a daily basis and could switch "on" or "off" daily, whereas the "cumulative exposure" measure reflected the percentage of follow-up days, also on a daily basis allowing it to switch on or off daily, for which the criterion was met. RESULTS: Two thousand nine hundred and fifty-four (54%) participants died during the follow-up period. Using the cumulative exposure measure, 27% never had continuity of care, whereas 31%, 20%, 14%, and 8%, respectively, had continuity for 1%-33%, 34%-67%, 68%-99%, and 100% of their follow-up days. Adjusted for demographics, socioeconomic status, social support, health lifestyle, and morbidity, both measures of continuity were associated (p < .001) with lower mortality (adjusted hazard ratios of 0.84 for the present exposure measure and 0.31, 0.39, 0.46, and 0.62, respectively, for the 1%-33%, 34%-67%, 68%-99%, and 100% categories of the cumulative exposure measure). CONCLUSION: Continuity of care with a PCP, as assessed by two distinct measures, was associated with substantial reductions in long-term mortality.

Recent hospitalization and the risk of hip fracture among older Americans.

BACKGROUND: We identified hip fracture risks in a prospective national study. METHODS: Baseline (1993-1994) interview data were linked to Medicare claims for 1993-2005. Participants were 5,511 self-respondents aged 70 years and older and not in managed Medicare. ICD9-CM 820.xx (International Classification of Diseases, 9th Edition, Clinical Modification) codes identified hip fracture. Participants were censored at death or enrollment into managed Medicare. Static risk factors included sociodemographic, socioeconomic, place of residence, health behavior, disease history, and functional and cognitive status measures. A time-dependent marker reflecting postbaseline hospitalizations was included. RESULTS: A total of 495 (8.9%) participants suffered a postbaseline hip fracture. In the static proportional hazards model, the greatest risks involved age (adjusted hazard ratios [AHRs] of 2.01, 2.82, and 4.91 for 75-79, 80-84, and > or =85 year age groups vs those aged 70-74 years; p values <.001), sex (AHR = 0.45 for men vs women; p < .001), race (AHRs of 0.37 and 0.46 for African Americans and Hispanics vs whites; p values <.001 and <.01), body mass (AHRs of 0.40, 0.77, and 1.73 for obese, overweight, and underweight vs normal weight; p values <.001, <.05, and <.01), smoking status (AHRs = 1.49 and 1.52 for current and former smokers vs nonsmokers; p values <.05 and <.001), and diabetes (AHR = 1.99; p < .001). The time-dependent recent hospitalization marker did not alter the static model effect estimates, but it did substantially increase the risk of hip fracture (AHR = 2.51; p < .001). CONCLUSIONS: Enhanced discharge planning and home care for non-hip fracture hospitalizations could reduce subsequent hip fracture rates.

Hospital episodes and physician visits: the concordance between self-reports and medicare claims.

BACKGROUND: Health services use typically is examined using either self-reports or administrative data, but the concordance between the 2 is not well established. OBJECTIVE: We evaluated the concordance of hospital and physician utilization data from self-reports and claims data, and identified factors associated with disagreement. METHODS: We performed a secondary analysis on linked observational and administrative data. A national sample of 4310 respondents who were 70 years old or older at their baseline interviews was used. Self-reported and Medicare claims-based hospital episodes and physician visits for 12 months before baseline were examined. Kappa statistics were used to evaluate concordance, and multivariable multinomial logistic regression was used to identify factors associated with overreporting (self-reports > claims), underreporting (self-reports < claims), and concordant-reporting (self-reports approximately claims). RESULTS: The concordance of hospital episodes was high (kappa = 0.767 for the 2 x 2 comparison of none vs. some and kappa = 0.671 for the 6 x 6 comparison of none, 1, ..., 4, or 5 or more), but concordance for physician visits was low (kappa = 0.255 for the 2 x 2 comparison of none versus some and kappa = 0.351 for the 14 x 14 comparison of none, 1, ..., 12, and 13 or more). Multivariable multinomial logistic regression indicated that over-, under-, and concordant-reporting of hospital episodes was significantly associated with gender, alcohol consumption, arthritis, cancer, heart disease, psychologic problems, lower body functional limitations, self-rated health, and depressive symptoms. Over-, under-, and concordant-reporting of physician visits were significantly associated with age, gender, race, living alone, veteran status, private health insurance, arthritis, cancer, diabetes, hypertension, heart disease, lower body functional limitations, and poor memory. CONCLUSIONS: Concordance between self-reported and claims-based hospital episodes was high, but concordance for physician visits was low. Factors significantly associated with bidirectional (over- and underreporting) and unidirectional (over- or underreporting) error patterns were detected. Therefore, caution is advised when drawing conclusions based on just one physician visit data source.