Cognitive Impainment and Hospital Use

..., 11.1.1.... I...... Philip G. Weiler, MD, MPH, * James E. Lubben, MPH, DSW, and Ins Ch, DSW Introduction was to examine the relation between cognitive status and hospitalization in a ran- Cognitive status has been identified domly selected cohort of community as one of the risk factors for nursing home dwelling Medicaid recipients. Addition- placement' but it has not been well studied ally, the study examined the relation of as a cause of hospitalization. Although cognitive status and length of hospital several studies have looked at health serv- stays. The cohort was followed for one ices utilization due to Alzheimer's Disease year. or other dementias,2-4 these studies have been mainly interested in estimating costs Methods of care, particularly cost of nursing home care.4 Further, they have relied largely on Design cross-sectional data sources and the num- The data were drawn from the Cali- ber of individuals with cognitive impair- fomia Senior Survey (CSS), a random ment in some of these data sets has been sample of community dwelling elderly small. MediCal (Medicaid) recipients from eight Few studies have looked at the hos- representative communities within Cali- pitalization admission rate and length of fomia. The CSS respondents were ran- stay in a random sample of community domly selected from files which contained dwelling elderly based on their cognitive the names, addresses, and other basic de- status. Huang and Hu2 found that the el- mographic data with all MediCal recipi- derly demented utilized an average of4.81 ents. Only MediCal recipients 65 years of days of short-term acute hospital care per age and older were sampled. CSS respon- person. This represented an additional uti- dents were interviewed face to face in lization of short stay hospitals due to their homes in 1982. Comparisons be- Alzheimer's Disease of0.81-1.02 days per tween the survey data and statewide data year based on the national hospital dis- indicated that respondents were typical of charge survey data. Coughlin and Liu,5 Califomia's MediCal elderly population.7 using data from the 1981-82 National More complete descriptions of the sam- Long-Term Care Channeling Demonstra- pling methodology and sample character- tion Project and the Short Portable Mental istics have already been published.7'8 Status Questionnaire (SPMSQ) to rate a Hospital utilization data were ob- person's cognitive status, found that the tained for one year following the inter- severely cognitively impaired spent a higher proportion of survival days in hospitals (.10) then mild/no cognitive im- *Dr. Philip G. Weiler has died since this study paired (.08) after six months of follow-up. was completed. Dr. Lubben is Associate Pro- fessor, School of Social Welfare, UCLA; Dr. More recently, Binder and Robins6 found Chi is Lecturer, Department of Social Work, that community dwelling elderly were University of Hong Kong. Address reprint re- more likely to be hospitalized if they quests to Dr. James Lubben, UCLA, School of scored poorly on the Folstein Mini-Mental Social Welfare, 247 Dodd Hall, 405 Hilgard Ave, Los Angeles, CA 90024. This paper, sub- State Exam. mitted to the Journal December 19, 1989, was In response to the limited research on revised and accepted for publication January 7, this topic, the purpose ofthe present study 1991.

American Journal of Public Health 1153 Wedler et al.

prehensive questionnaire composed of several previously described instruments.13 Included in this batterywere two commonly used functional status scales: the Activity of Daily Living (ADL) and Instrumental Activity of Daily Living (IADL) scale.14,15 Two dichotomous variables measur- ing hospital utilizationwere used: whether a respondent had been hospitalized within the year following the interview, and whether a respondent experienced a hospital stay of six or more days in the year following the interview. The figure of six days was selected because it was slightly higher than the average length of stay for all respondents (mean length ofstay = 5.2 days). Analysis The present analyses used bivariate analyses (Chi-square) and odds ratios. A series of logistic regression models were used to examine the relation of the levels of cognitive status with the two indices of subsequent hospital utilization. Age, education, race, and prior hospitalizations during the year prior to the survey were controlled. The statistical program used was SAS and analyses were conducted on view. The hospital utilization data came No significant differences in terms of an IBM 3090 mainframe computer. from MediCal paid claims and computer major sociodemographic and health status tapes which were merged with data ob- characteristics were noted between sur- Study Population tained from Medicare intermediaries.9 vey respondents with and without com- Combining these two sources provided plete data. All respondents with complete Reflecting the diversity of Califor- data on number ofdays hospitalized for 92 hospital and cognitive status data were nia's ethnic population, the sample in- percent of the original CSS sample (N = used for the study analyses (N = 940). cluded a sizable portion ofBlacks (17 per- 1,037). To assure accuracy, the computer A structured measure of mental sta- cent), Hispanic (13 percent), and Asians tapes were examined for any bills submit- tus was administered, the Short Portable (12 percent), although a majority (58 per- ted for hospitalization during the follow- Mental Status Questionnaire (SPMSQ). cent)were White. Seventy-twopercentof up year to either MediCal or Medicare in- This instrument has high validity and test- the sample were females and over 60 per- termediaries on behalf of CSS retest reliability.10 The widely used test is cent of the sample lived alone. The age respondents. To overcome any problems a 10-item questionnaire that is designed to distribution of the sample was 42 percent that may have been caused by late billing, measure several areas of intellectual do- (65-74 years of age), 44 percent (75-84 bills submitted up to two years following main including orientation, short- and years old), and 14 percent (85 years old the interview were reviewed. long-term memory, general information, and over). The majority of participants Besides those without hospital data, and problem solving. Pfeiffer10 originally were widowed (56 percent) with 23 per- 15 other respondents were also dropped recommended adjustments for race and cent being married, 6 percent single, and from the present study. Six lacked cogni- education. However, more recent ver- 15 percent separated or divorced. The ed- tive status data and nine had died within a sions of the SPMSQ only adjust for edu- ucational level obtained by the partici- few months ofthe survey and so their hos- cation.11'12 Thus the present analysis pants was 33 percent finished high school pital data were necessarily censored. chose to only adjust SPMSQ scores for and 19 percent had an education beyond Analyses were run with and without these education, although both race and educa- high school, 6 percent had no formal ed- six respondents and they did not signifi- tion were entered as covariates in the mul- ucation, and about 42 percent finished el- cantly affect the outcome. However, tiple regression analysis. ementary school. dropping these six respondents from the Using Pfeiffer's recommendations, analyses was considered the more appro- the SPMSQ scores used to categorize par- priate method. Although 25 other respon- ticipants were: not impaired (0-2 errors), Resmdt dents also had died within a year of the mildly impaired (3-4 errors), and moder- baseline survey, they all had extensive ately to severely impaired (over 4 er- Table 1 gives selected characteristics hospital stays before their death and so it rors).10 The SPMSQ was administered in of the participants by level of cognitive was possible to properly classifytheir hos- the elderly person's home by trained in- impairment. Overall about 17 percent of pital use for the present analyses. terviewers who also administered a com- the study population was either mildly or

1154 American Journal of Public Health September 1991, Vol. 81, No. 9 Cognitive Function, Elderly Hospital Use

moderately to severely impaired. There was a higher prevalence of cognitive impairment in females than males. The prevalence of cognitive impairment increased significantly with age. Marital status was not related to cognitive impairment but cognitive impairment was more prevalent in those living with others than in those living alone. There were no race or eth- nicity differences in the prevalence ofcognitive impairment, but lack of education was associated with cognitive impairment. Therewas a significantly higher prevalence of cognitive impairment in those participants with two or more ADL dependencies. Similarly, an increased num- berofinstrumental activities ofdailyliving (IADL) dependencies was also significantly associated with cognitive impairment with money management having the strongest association (Table 2). The number oftotal chronic conditions was not significantly related to cognitive impairment (Table 3). Arthritis was negatively associated with cognitive impairment whereas stroke was positively related. Odds ratios adjusted for age, education, race, and any hospitalizations during year prior to survey are shown in Table 4. Those participants with cognitive impairment were more likely to be hospitalized and to have increasing length of hospitalizations. Similarly, greater impairments on the ADL and IADL scales were associated with increased risk of hospitalization. The number of dependencies on the ADL and IADL was collapsed into cate- ADL was not generally associated with cially strong predictor of future hospital gories to facilitate analyses. Very few re- increased risk of hospital use. use evenwhen controlling for moderate to spondents had more than two ADL de- Among the covariates, having been severe impairments on the SPMSQ. pendencies and so a single dependency on hospitalized during the year prior to the the ADL was considered a mild ADL im- survey and being White were the only co- Discussion pairmentwhereas being unable to perform variates related to subsequent hospital two or more ADL functions was consid- use. Previous hospitalization was the only The data are consistentwith previous ered to be a moderate to severe ADL im- covariate predictor of subsequent stays of findings that cognitive impairment in com- pairmnent. Cut points for the IADL were six or more days (OR 2.73; CI = 1.96, munity dwelling elderly is more common selected to maxinize the relationship be- 3.81). among females, older age groups, and tween IADL and hospital use. One to two To directly compare the SPMSQ those living with others.1617 The preva- IADL dependencies were judged to be a with the ADL and IADL as predictors of lence rates of cognitive impairment in mild IADL impairment, three to four a hospitalization, additional logistic regres- studies of community elderly vary from a moderate impairment, and five or more sion models were constructed. One set of low of 1.6 percent (severe impairment) to IADL dependencies were classified as a models included both the SPMSQ and the a high of over 15 percent for the mildly severe dependency. Any level of impair- ADL. Another set included the SPMSQ impaired. The present study found an ment on the SPMSQ was predictive of and the IADL (the ADL and IADL were overall rate of 16.7 percent. The preva- hospital use. Increased impairment on any too highly correlated to have included lence of cognitive impairment among the of the scales was associated with in- both ofthese functions in the same regres- old old (85 years of age and older) was creased risk of extended hospital stays. sion models). In these direct comparisons, found to be higher (32.8 percent) than that Further, Table 4 illustrates that those el- the SPMSQ proved to be more predictive previously reported (25 percent).16 Two derly with severe IADL impairments are of future hospital use than the ADL but recent studies have also found higher than especially at increased risk of longer hos- not as good as the IADL. Five or more expected prevalence rates in the old old. pitalizations. Mild impairment on the dependencies on the IADL was an espe- Forty seven percent of those 85 years old

September 1991, Vol. 81, No. 9 American Journal of Public Health 1155 Weiler et al.

ment and length of hospital stay in older o v"f S- Es:::'ZS-''fVEviSS'sf''2'R.S'SSSS''S S- '22persons. J Am Geriatr Soc 1990; 38:759- 766...... 7. Miller LS, Clark ML, Clark WF: The com- parative evaluation of California's Multi- purpose Senior Services Project (MSSP). Home Health Care Serv Q 1985; 6:49-79. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~....-'...... S.SS.^*' 8. ClarkWF, PelhamAO, Clark ML: Old and ~~~~~~~~~~~~~~~~~.... i...... ,....-, ,f.,,o.....l poor. Lexington, MA: Lexington Books, iesii sSe os s- g ¢>}S } .., ¢ ¢ ¢...... '.'' S''' 1988. ''f''''i10e-...... 9. Clark ML, Walter L, Miller LS: Estimates of medical services cost: MediCal and .- :5.:-: .:::.::g ff }X -|- ..>...... S.s Medicare paid claims. Berkeley, CA: Mul- tipurpose Senior Services Project (MSSP) Evaluation Unit, 1983. S,.,,,.,f,.S2,,,{, ~~~~~~~~~~~~~~~~~~~~~~~~~..... >.,.... i ...... , ...-. x--S 10. Pfeiffer E: A short portable mental status x, e,~~~~~~~~~~~~~~~~~~~~~~~~~~~~ questionnaire for the assessment oforganic brain deficit in elderly patients. J Am Geri- atr Soc 1975; 23:433-441. 11. Pfeiffer E: The psychosocial evaluation of the elderly patient. In: Busse EW, Blazer DE (eds): Handbook of Geriatric Psychia- try. New York: Van Nostrand Reinhold, 1980. 12. Gao JJ, Reichel W, Anderson L: Hand- or older were found to have probable average hospital stays even after control- book of Geriatric Assessment. Rockville, Alzheimer's disease inone studyconducted ling for age, ADL, IADL, and prior hos- MD: Aspen Publications, 1988. in a geographically defined community in pitalizations. The longer length of stay 13. Lubben JE: Health and psychological assessment instruments for community which 80.8% of the age-eligible residents maybe due to lackofappropriate posthos- based long-term care: The California Mul- were evaluated.18 In another study of de- pital placement or to complications ofhos- tipurpose Senior Services Project (MSSP) mentia in a retirement community, Pfeffer19 pitalization.23'24 Whatever the reasons for experience. Doctoral dissertation, Univer- found theprevalence rateofdementias tobe increased hospital use, the increasing sity of California, Berkeley, 1984. old and older. prevalence ofcognitively impaired elderly 14. Katz S, Ford AB, Moskokwitz RW, Jack- 56.7 percent in those 85 years son B, Jaffe MW: Studies of illness in the Although comparisons amongvarious stud- will result in an enormous financial burden aged: The index of ADL: A standardized ies are difficult due to differing methods of for the patient, family, and government measure of biological and psychological case ascertaimnent, sampling methods and and has significant public health conse- function. JAMA 1963; 185:914-919. study populations, these data suggest that quences.2526 E 15. Lawton MP, Brody EM: Assessment of older people: Self-maintaining and instru- the public health impact ofcognitive impair- mental activities of daily living. Gerontol- ment in the elderly maybe greater than pre- ogist 1969; 9:179-186. viously descnibed. Acknowledgments 16. Cross PS, Gurland BJ: The epidemiology Our data do not support the concept of dementing disorders. Washington, DC: The data used in this analysis come from the US Congress, Office of Technology As- of a racial or ethnic difference in cognitive California Senior Survey, which was the com- sessment, 1985. impairment as implied in earlier sugges- parison group for the California Multipurpose 17. Mortimer JA, Schuman LM, French LR: tionsforadjusted scoringofthe SPMSQ.10 Senior Services Project (MSSP), a US Health Epidemiology: Overview and prospects. The data did show a significant association Care Finance Administration (HCFA 115) re- In: Mortimer JA, Schuman LM (eds): The between educational level and perfor- search and demonstration project (Grant #11- Epidemiology of Dementia. New York: P-07553). Oxford University Press, 1981. mance on mental status examinations. This project was funded in part by the Cal- 18. Evans DA, Funkenstein HH, Albert MS, This association has been documented in ifornia Academic Geriatric Resource Program. Scherr PA, Cook NR, Chown MJ, Herbert other studies as well.20 For example, LE, Hennekens CH, Taylor JO: Preva- Katzman21 studied a probability sample of References lence of Alzheimer's disease in a commu- in 1. Branch LG, Jette AL: A prospective study nity population of older persons. JAMA 5,055 community dwelling elderly of long-term care institutionalization 1989; 262:2551-2556. Shanghai. The Chinese Mini-Mental State among the aged. Am J Public Health 1982; 19. Pfeffer RI, Afifi AA, Chance JM: Preva- (CMMS) was used to evaluate mental sta- 72:1373-1379. lence ofAlzheimer's disease in a retirement tus. In comparison to those with formal 2. Huang L, Hu T: Economic costs of senile community. Am J Epidemiol 1987; education, this study found significantly dementia in the United States. National In- 125:420-436. stitute on Aging, Control No. N 01-AG-3- 20. King H, Locke F: Health risk and lifestyle. lower scores on the mental status test as 2123. Washington, DC: Applied Systems In: Rothschild H (ed): Risk Factors for Se- well as a different error pattern among the Institute, 1983. nility. NewYork: Oxford UniversityPress, uneducated even after making adjust- 3. Hay JW, Ernst RL: The economic costs of 1984. ments for education. The reason for the Alzheimer's disease. Am J Public Health 21. Katzman R, Zhang MY, Quang Ya Qu, association between educational level and 1987; 77:1169-1175. Wang ZY, Liu WT, Yu E, Wong SC, 4. Coughlin T, Liu K: Health care costs of Salmon DP, Grant I: A Chinese version of suggested cognitive impairment has not dementia: A review. Washington, DC: the Mini-Mental State Examination; im- yet been fully explained.22 Health Policy Center, Urban Institute, pact of illiteracy in a Shanghai dementia Although the cause of the cognitive September 1987. survey. J Clin Epidemiol 1988; 41:971-978. impairment and hospitalization were not 5. Coughlin T, Liu K: Health care costs of 22. Berkman LF: The association between ed- older persons with cognitive impainnents. ucational attainment and mental status ex- determined in this study, the data indicate Washington, DC: Urban Institute, January aminations: Ofetiologic significance for se- that cognitive impairment is a risk factor 1988. nile dementias or not? J Chronic Dis 1986; for hospital admissions and longer than 6. Binder EF, Robins LN: Cognitive impair- 39:171-175.

1156 American Journal of Public Health September 1991, Vol. 81, No. 9 Cognitive Function, Elderiy Hospitl Use

23. Johnston M, Wakeling A, Graham N, 24. Erldnjuntti T, Autio L, Wikstrom J: De- 26. US Congress, Office of Technology As- Stokes F: Cognitive impairment, emo- mentia in medical wards. J Clin Epidemiol sessment: Losing a Million Minds: Con- tional disorder and length of stay of 1988; 41:123-126. fronting the Tragedy of Alzheimer's Dis- elderly patients in a district general hospi- 25. Weiler PG: The public health impact of ease and Other Dementias. Pub. No. OTA- tal. Br J Med Psychol 1987; 60:133- Alzheimer's disease. Am J Public Health BA-323. Washington, DC: Govt Printing 139. 1987; 77:1157-1158. Office, 1987.

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September 1991, Vol. 81, No. 9 American Journal of Public Health 1157