Scand J Soc Med, Vol. 20, No.2
Diseases and symptoms as predictors of hospital care in an aged population A prospective register-based study
Sari K. Anttila Department of Public Health, University of Tampere, Finland
Diseases ami symptoms as predictors of hospital care ill all aged population. A prospective register-based study, Scand J Soc Med 1992, 20 (79-84).
The association between diseases and symptoms and general hospital care was studied in a geographically defined population of I 040 persons aged 65 years or over (90% of the eligible non-institutionalized elderly). In eight years, 25% of the subjects used over 60 hospital bed-days. In age-controlled analyses high use of hospital care was predicted by chronic urinary infections and in women also by chronic bronchitis, diabetes mellitus and heart failure. Among men, the risk of high use of hospital care was greatest in those reporting chronic urinary infection (risk ratio 1.9), and among women in those reporting chronic bronchitis (2.1) and diabetes (2.0). As far as symptoms were concerned, the highest risks of hospital care were found in men reporting tremor (risk ratio 1.6) and depressive symptoms (1.5); and in women reporting memory disturbances and dizziness (risk ratios 1.9 and 1.7, respectively). High use of care was predicted by six symptoms in men and seven in women. Reported symptoms proved to be better predictors of high use of hospital care than reported diagnoses. Key words: Old age, chronic disease, hospital utilization, health services research, linear models
INTRODUCfION Patterns of health care utilization among the elderly are causing growing concern among health care professionals and policy makers in Europe. The use of hospital bed-days, the most expensive resource in the health care system, increases dramatically with age. According to a Finnish national survey (1), the usc of general hospital bed-days doubles in each older five-year age group after the age of 65. Combined with the projected increase in the very old population in industrialized countries over the next two decades (2), this has created widespread interest in predictors of hospital care in the elderly. The aim is to postpone the need for long-term care in hospi-
tals by prophylactic measures for the elderly population at risk. Most aged persons, 70-80% in a Finnish study (3), prefer living at home as long as possible. In earlier reports large diagnostic groups have been studied for causes of general hospital care (4,5). However, most studies are based on hospital samples of aged persons (4,6), and these are not necessarily representative of the general population. Furthermore, follow-ups have been typically restricted to only a few years (4,5,6). Based on register information during an eightyear period, the aim of this study was to find out which diseases and symptoms predict prospective high use of hospital bed-days. This knowledge could then be used to identify risk groups in the elderly population, diagnose and treat diseases and symptoms and, hopefully, decrease the use of hospital bed-days in the elderly. SUBJECTS AND METHODS A total non-institutionalized population aged 65 or over was interviewed in 1978 in Kuusamo, a large municipality in northern Finland (7,8). All the elderly were sent a personal invitation to an interview and a questionnaire concerning specified common diseases in old age (9) diagnosed or treated by a doctor during the preceding year. This gave the elderly persons sufficient time to recall their diseases. Further on, the analysis of somatic diseases was restricted to those with a prevalence in excess of 10 percent for either sex and to myocardial infarction and cerebrovascular diseases, which require hospital care. In a structured interview district nurses asked the elderly about demographic background data and the Scand J Soc Med 20
Downloaded from sjp.sagepub.com at TEXAS A & M INTL UNIV on March 14, 2015
S. K. Anttila
80
days
798J 150 140
I
130
120 110
100 90 80 70 60 50 40 30 20 10
follow-up, these persons were followed for a shorter period than 8 years. As the aim of the study was to identify elderly at risk of high use of hospital care, the population was divided into high users and low users of hospital care. This made it possible to study the association of specific diseases and symptoms with high use of hospital care by cross tabulations, risk ratios and by age-controlled log-linear analysis (13) using the 4f program of BMDP. High use of hospital care was defined so as to have a risk group representing not more than one quarter of the total material.
RESULTS
0-1--J...--e~L.--'--L----L.-.I--L...L.---'---l
o 10 20 30 40 50 60 70 80 90 100 %
Figure I. Distribution of the hospital days (%) in eight years in persons aged 65 years or over (N = 10-10).
presence of symptoms common in elderly populations (9,10) and severe enough to affect activities of daily living. Data on treatment of the participants in all general hospitals in Finland were derived by record linkage from the National Hospital Discharge Register for 1979-86 by means of personal identification numbers. The register lists all inpatient admissions (acute, long-term and rehabilitative care) to general hospital wards and the dates of the first and last day in hospital care. According to a survey (II) 90-95% of all admissions to hospitals are registered. The data were processed by BMDP (12). The significance of differences between the means was tested by the r-test, and X2 statistics were also used. Hospital discharge data based on individual identifiers captured the very skewed nature of hospitalization patterns, most of the elderly using remarkably few and some very many hospital bed-days (Figure I). As some of the study persons died during the
Of the eligible non-institutionalized elderly, 10-l0 persons or 90% participated in the study. Ninetyfive aged persons in institutions were excluded. The proportion of males was 41%.Twenty-seven percent of the elderly were aged 75 or over, and 79% had been employed in agriculture before retirement. The non-participants were mostly older women (7). The most common disease diagnosed or treated in elderly men was hypertension or high blood pressure, the prevalence of which was 28% (Table I). The lowest prevalence was found for cerebrovascular diseases, which was reported by 2% of the men. Hypertension or high blood pressure was reported by 50% of the women. Cerebrovascular diseases (2%) and neurologic or psychiatric illness (2%) were the least common diseases in women. The most common symptoms in men were memTable I. Prevalences of diseases diagnosed or treated by a doctor during the preceding year ill a total population (N = 1034). Men N=430 %
Hypertension/high blood pressure Heart failure Degenerative disease of the spine Osteoarthrosis Chronic bronchitis/emphysema Angina pectoris Chronic urinary infection/cystitis Myocardial infarction Rheumatoid arthritis Diabetes mellitus Neurologicor psychiatricdisease Cerebrovascular diseases
.Scand J Sc Med 20
Downloaded from sjp.sagepub.com at TEXAS A & M INTL UNIV on March 14, 2015
27.9 26.3 24.4 22.6 20.0 16.3 11.6 10.0 7.7 5.6 2.6
2.3
Women N=6W %
50.2 35.4 21.4 28.3
4.5
13.2 27.5
4.5
12.6 13.1 2.0
2.3
Diseases and symptoms as predictors of hospital care Table II. Prevalences of symptoms in a total population (N = 1034) Men N=430 %
Women N=604 % 47.7 27.5 46.5
Memory disturbances 38.8 Low back pain 38.8 Pain in the joints of the lower limb 38.6 Pain in the joints of the upper limb 33.0 Dyspnoea 32.6 Chest pain 30.7 Dizziness 21.6 Depressive symptoms 12.6 Tremor 11.2
4I.l
20.0 23.8 28.8 13.6 13.4
ory disturbances (39%) and low back pain (39%) (Table II). Memory disturbances was also the most common symptom in women (48%). Tremor was the least common complaint both in men (11%) and in women (13%). The use of hospital days varied from zero to 798 days in eight years (Figure I). The mean number of hospital days in eight years was 56.9 (men 61.2, women 53.8 days, p > 0.05). Older persons used 70.8 and those aged 65-74 years 51.7 days (p < 0.01). Eighty percent had been admitted at least
once to general hospitals, 86% of the persons aged 75 or over and 78% of the younger ones (p < 0.01). Twenty-five percent of the subjects had used 60 or more hospital days in eight years. These elderly were defined as high users of hospital care. Among the men and women reporting chronic urinary infections, 48% and 30%, respectively, became high users of hospital care (Table III). Forty-four percent of the women reporting chronic bronchitis and 41% of those reporting diabetes became high users of care. In age-controlled log-linear models for women, four of the 12 diseases were statistically significant predictors of high use of care (Table III). The greatest risk of becoming a high user of care was found for women reporting chronic bronchitis/emphysema (risk ratio 2.1) and diabetes (2.0). Heart failure and chronic urinary infection/cystitis also predicted high use of hospital care. In men, only chronic urinary infection/cystitis showed a statistically significant connection with high use of hospital care. The risk of becoming a high user of care was 1.9-fold in men reporting chronic urinary infection compared to men without this disease. All of the nine symptoms showed a statistically significant association with high use of hospital care
Table III. High use ofhospital care and risk ratios by reported diseasesin a total elderly population (N
Diseases Chronic urinary infection/cystitis present absent Diabetes mellitus present absent Chronic bronchitis/emphysema present absent Heart failure present absent
81
High use of hospital care" in 8 years
Risk ratios"
Men N=430 %
Men N=430
p
Women N=604 %
48.0 25.3
Diseases and symptoms as predictors of hospital care in an aged population A prospective register-based study
Sari K. Anttila Department of Public Health, University of Tampere, Finland
Diseases ami symptoms as predictors of hospital care ill all aged population. A prospective register-based study, Scand J Soc Med 1992, 20 (79-84).
The association between diseases and symptoms and general hospital care was studied in a geographically defined population of I 040 persons aged 65 years or over (90% of the eligible non-institutionalized elderly). In eight years, 25% of the subjects used over 60 hospital bed-days. In age-controlled analyses high use of hospital care was predicted by chronic urinary infections and in women also by chronic bronchitis, diabetes mellitus and heart failure. Among men, the risk of high use of hospital care was greatest in those reporting chronic urinary infection (risk ratio 1.9), and among women in those reporting chronic bronchitis (2.1) and diabetes (2.0). As far as symptoms were concerned, the highest risks of hospital care were found in men reporting tremor (risk ratio 1.6) and depressive symptoms (1.5); and in women reporting memory disturbances and dizziness (risk ratios 1.9 and 1.7, respectively). High use of care was predicted by six symptoms in men and seven in women. Reported symptoms proved to be better predictors of high use of hospital care than reported diagnoses. Key words: Old age, chronic disease, hospital utilization, health services research, linear models
INTRODUCfION Patterns of health care utilization among the elderly are causing growing concern among health care professionals and policy makers in Europe. The use of hospital bed-days, the most expensive resource in the health care system, increases dramatically with age. According to a Finnish national survey (1), the usc of general hospital bed-days doubles in each older five-year age group after the age of 65. Combined with the projected increase in the very old population in industrialized countries over the next two decades (2), this has created widespread interest in predictors of hospital care in the elderly. The aim is to postpone the need for long-term care in hospi-
tals by prophylactic measures for the elderly population at risk. Most aged persons, 70-80% in a Finnish study (3), prefer living at home as long as possible. In earlier reports large diagnostic groups have been studied for causes of general hospital care (4,5). However, most studies are based on hospital samples of aged persons (4,6), and these are not necessarily representative of the general population. Furthermore, follow-ups have been typically restricted to only a few years (4,5,6). Based on register information during an eightyear period, the aim of this study was to find out which diseases and symptoms predict prospective high use of hospital bed-days. This knowledge could then be used to identify risk groups in the elderly population, diagnose and treat diseases and symptoms and, hopefully, decrease the use of hospital bed-days in the elderly. SUBJECTS AND METHODS A total non-institutionalized population aged 65 or over was interviewed in 1978 in Kuusamo, a large municipality in northern Finland (7,8). All the elderly were sent a personal invitation to an interview and a questionnaire concerning specified common diseases in old age (9) diagnosed or treated by a doctor during the preceding year. This gave the elderly persons sufficient time to recall their diseases. Further on, the analysis of somatic diseases was restricted to those with a prevalence in excess of 10 percent for either sex and to myocardial infarction and cerebrovascular diseases, which require hospital care. In a structured interview district nurses asked the elderly about demographic background data and the Scand J Soc Med 20
Downloaded from sjp.sagepub.com at TEXAS A & M INTL UNIV on March 14, 2015
S. K. Anttila
80
days
798J 150 140
I
130
120 110
100 90 80 70 60 50 40 30 20 10
follow-up, these persons were followed for a shorter period than 8 years. As the aim of the study was to identify elderly at risk of high use of hospital care, the population was divided into high users and low users of hospital care. This made it possible to study the association of specific diseases and symptoms with high use of hospital care by cross tabulations, risk ratios and by age-controlled log-linear analysis (13) using the 4f program of BMDP. High use of hospital care was defined so as to have a risk group representing not more than one quarter of the total material.
RESULTS
0-1--J...--e~L.--'--L----L.-.I--L...L.---'---l
o 10 20 30 40 50 60 70 80 90 100 %
Figure I. Distribution of the hospital days (%) in eight years in persons aged 65 years or over (N = 10-10).
presence of symptoms common in elderly populations (9,10) and severe enough to affect activities of daily living. Data on treatment of the participants in all general hospitals in Finland were derived by record linkage from the National Hospital Discharge Register for 1979-86 by means of personal identification numbers. The register lists all inpatient admissions (acute, long-term and rehabilitative care) to general hospital wards and the dates of the first and last day in hospital care. According to a survey (II) 90-95% of all admissions to hospitals are registered. The data were processed by BMDP (12). The significance of differences between the means was tested by the r-test, and X2 statistics were also used. Hospital discharge data based on individual identifiers captured the very skewed nature of hospitalization patterns, most of the elderly using remarkably few and some very many hospital bed-days (Figure I). As some of the study persons died during the
Of the eligible non-institutionalized elderly, 10-l0 persons or 90% participated in the study. Ninetyfive aged persons in institutions were excluded. The proportion of males was 41%.Twenty-seven percent of the elderly were aged 75 or over, and 79% had been employed in agriculture before retirement. The non-participants were mostly older women (7). The most common disease diagnosed or treated in elderly men was hypertension or high blood pressure, the prevalence of which was 28% (Table I). The lowest prevalence was found for cerebrovascular diseases, which was reported by 2% of the men. Hypertension or high blood pressure was reported by 50% of the women. Cerebrovascular diseases (2%) and neurologic or psychiatric illness (2%) were the least common diseases in women. The most common symptoms in men were memTable I. Prevalences of diseases diagnosed or treated by a doctor during the preceding year ill a total population (N = 1034). Men N=430 %
Hypertension/high blood pressure Heart failure Degenerative disease of the spine Osteoarthrosis Chronic bronchitis/emphysema Angina pectoris Chronic urinary infection/cystitis Myocardial infarction Rheumatoid arthritis Diabetes mellitus Neurologicor psychiatricdisease Cerebrovascular diseases
.Scand J Sc Med 20
Downloaded from sjp.sagepub.com at TEXAS A & M INTL UNIV on March 14, 2015
27.9 26.3 24.4 22.6 20.0 16.3 11.6 10.0 7.7 5.6 2.6
2.3
Women N=6W %
50.2 35.4 21.4 28.3
4.5
13.2 27.5
4.5
12.6 13.1 2.0
2.3
Diseases and symptoms as predictors of hospital care Table II. Prevalences of symptoms in a total population (N = 1034) Men N=430 %
Women N=604 % 47.7 27.5 46.5
Memory disturbances 38.8 Low back pain 38.8 Pain in the joints of the lower limb 38.6 Pain in the joints of the upper limb 33.0 Dyspnoea 32.6 Chest pain 30.7 Dizziness 21.6 Depressive symptoms 12.6 Tremor 11.2
4I.l
20.0 23.8 28.8 13.6 13.4
ory disturbances (39%) and low back pain (39%) (Table II). Memory disturbances was also the most common symptom in women (48%). Tremor was the least common complaint both in men (11%) and in women (13%). The use of hospital days varied from zero to 798 days in eight years (Figure I). The mean number of hospital days in eight years was 56.9 (men 61.2, women 53.8 days, p > 0.05). Older persons used 70.8 and those aged 65-74 years 51.7 days (p < 0.01). Eighty percent had been admitted at least
once to general hospitals, 86% of the persons aged 75 or over and 78% of the younger ones (p < 0.01). Twenty-five percent of the subjects had used 60 or more hospital days in eight years. These elderly were defined as high users of hospital care. Among the men and women reporting chronic urinary infections, 48% and 30%, respectively, became high users of hospital care (Table III). Forty-four percent of the women reporting chronic bronchitis and 41% of those reporting diabetes became high users of care. In age-controlled log-linear models for women, four of the 12 diseases were statistically significant predictors of high use of care (Table III). The greatest risk of becoming a high user of care was found for women reporting chronic bronchitis/emphysema (risk ratio 2.1) and diabetes (2.0). Heart failure and chronic urinary infection/cystitis also predicted high use of hospital care. In men, only chronic urinary infection/cystitis showed a statistically significant connection with high use of hospital care. The risk of becoming a high user of care was 1.9-fold in men reporting chronic urinary infection compared to men without this disease. All of the nine symptoms showed a statistically significant association with high use of hospital care
Table III. High use ofhospital care and risk ratios by reported diseasesin a total elderly population (N
Diseases Chronic urinary infection/cystitis present absent Diabetes mellitus present absent Chronic bronchitis/emphysema present absent Heart failure present absent
81
High use of hospital care" in 8 years
Risk ratios"
Men N=430 %
Men N=430
p
Women N=604 %
48.0 25.3
