Standardized Hospitalization Ratios Research Articles

Risks for Central Nervous System Diseases among Mobile Phone Subscribers: A Danish Retrospective Cohort Study

The aim of this study was to investigate a possible link between cellular telephone use and risks for various diseases of the central nervous system (CNS). We conducted a large nationwide cohort study of 420 095 persons whose first cellular telephone subscription was between 1982 and 1995, who were followed through 2003 for hospital contacts for a diagnosis of a CNS disorder. Standardized hospitalization ratios (SHRs) were derived by dividing the number of hospital contacts in the cohort by the number expected in the Danish population. The SHRs were increased by 10–20% for migraine and vertigo. No associations were seen for amyotrophic lateral sclerosis, multiple sclerosis or epilepsy in women. SHRs decreased by 30–40% were observed for dementia (Alzheimer disease, vascular and other dementia), Parkinson disease and epilepsy among men. In analyses restricted to subscribers of 10 years or more, the SHRs remained similarly increased for migraine and vertigo and similarly decreased for Alzheimer disease and other dementia and epilepsy (in men); the other SHRs were close to unity. In conclusion, the excesses of migraine and vertigo observed in this first study on cellular telephones and CNS disease deserve further attention. An interplay of a healthy cohort effect and reversed causation bias due to prodromal symptoms impedes detection of a possible association with dementia and Parkinson disease. Identification of the factors that result in a healthy cohort might be of interest for elucidation of the etiology of these diseases.

Research on the health state of the Sicilian population living in areas at environmental or natural risk: the experience of the Regional Department of Epidemiology

Background: In Sicily, people live near areas characterized by the presence of environmental polluting substances derived from urbanization and industrialization. In the areas of Augusta-Priolo (SR),Gela (CL) and Milazzo (ME), the increase of number of pathologies could be linked with environmental pollution. The aim of this paper is to present an overview of the available data and studies to underline the importance of these sources to conduct epidemiological survey in Sicily, besides to the analysis of mortality and morbidity. Methods: An evaluation of the health status of the residential population was done comparing the mortality and morbidity of the local population with the mortality and morbidity of a reference population. Data was obtained from the Italian national office of statistics and Hospital Discharge Records. Standardized Mortality Ratios and Standardized Hospitalization Ratios were calculated. Results: In the area of Augusta-Priolo we observed, in for men, a significative increase in mortality and hospital admissions for colon-rectal, trachea, bronchus, lung and pleura cancers. In Biancavilla, we observed an increase in mortality for pleura cancer in men and women and an increase in morbidity in women only. In Gela, a significant increase in mortality in males and females was observed only for tumoral diseases. In Milazzo, we only found a significant increase in the incidence of larynx cancer and cardiovascular disease for men and in women of pulmonary disease for women. Conclusions: This first review allowed us to update previous analyses of mortality data conducted in the same areas. The results, even taking into account the differences between the areas,, highlights changes in health status related to some diagnostic groups. These could be linked with pollution. Now that the available health data has been revised and updated new studies must be conducted.

Locomotor diseases among male long-haul truck drivers and other professional drivers

High risks for locomotor diseases have been reported for bus and truck drivers in general; however, little is known about the specific risks of long-haul truck drivers. Standardised hospitalisation ratios (SHR) for different locomotor diseases of bus drivers, long-haul truck drivers and other truck drivers were compared with each other and with the general Danish working population. Intervertebral disc disorders were more common among professional drivers (SHR: 119, 95% CI: 114-125) and of similar magnitude for cervical and non-cervical disorders. Both long-haul truck drivers and bus drivers had higher SHR for intervertebral disc disorders (SHR: 133, 95% CI: 114-155/SHR: 141, 95% CI: 129-154, respectively) than other truck drivers (SHR: 109, 95% CI: 102-116). The SHR for carpal tunnel syndrome was high among long-haul drivers (SHR: 163, 95% CI: 101-249) and for other truck drivers (SHR: 130, 95% CI: 108-156) compared to bus drivers (SHR: 110, 95% CI: 79-149). All drivers had high SHR for lesions of the ulnar nerve (SHR: 159, 95% CI: 119-207), especially bus drivers (SHR: 197, 95% CI: 116-311). Long-haul truck drivers had high SHRs for synovitis and bursitis (SHR: 150, 95% CI: 105-207), in contrast to other truck drivers and bus drivers (SHR: 103, 95% CI: 89-120/SHR: 87, 95% CI: 66-112, respectively). All groups of professional drivers experience high risk of various disorders of the locomotor system but type of vehicle and specific working conditions are associated with different health effects on the locomotor system.

Health Care Supply for Cataract in Austrian Public and Private Hospitals

This study aims to explain spatial variability or cataract and cataract surgery in Austria. The effect of the availability of health care services on spatial variation is investigated. A retrospective study, using routine hospital data from all Austrian public and private hospitals. Calculation of age- and gender-standardized hospitalization ratios (SHR) for all 121 Austrian districts. Poisson regression for age-specific relative risks was performed. The authors found high regional variability between districts and significant differences in the hospitalization rates of cataract disease and extraction between men and women. There was a significant correlation between standardized hospitalization ratios for districts and the availability of hospitals with departments of ophthalmology. There was a significant difference in length of stay for patients with cataract surgery between public and private hospitals. Use of routine hospital data in geographic analysis allows large regional studies on health care supply for cataract surgery. Differences in the supply by hospitals between districts depend on the availability of hospitals with departments of ophthalmology. The overall demand for cataract surgery in Austria finds its proper supply in many Austrian regions, but needs further development.

High familial risks for cerebral palsy implicate partial heritable aetiology

Cerebral palsy is the commonest cause of severe childhood disability, the aetiology of which is largely unknown. Data on familial aggregation of cerebral palsy are very limited. We defined familial risks for siblings who were hospitalised because of cerebral palsy in Sweden. A nationwide database for neurological diseases was constructed by linking the Multigeneration Register to the Hospital Discharge Register for the years 1987-2001. Standardised hospitalisation ratios (SHRs) were calculated for affected singletons and twins by comparing them with siblings who had no cerebral palsy. A total of 3997 patients were recorded with cerebral palsy. Familial cerebral palsy was uncommon, and it accounted for 1.6% of all cerebral palsy cases. However, for parents who had had one affected child the risk of recurrence in another child was considerably increased. Parents of one affected child had a 4.8-fold risk of having a second affected child, and where the siblings were twins, the risk was 29-fold. These familial risks were particularly high in some clinical subgroups: 17-25 in singletons and 37-155 in twins, including hemiplegia, diplegia and quadriplegia. The remarkably high familial risks are difficult to explain without some contribution of heritable factors. The lack of discordant pairs may suggest that heritable factors are disorder type-specific. Affected concordant sibling pairs should be subjected to molecular studies aiming at identifying the susceptibility gene.

Stroke among male professional drivers in Denmark, 1994–2003

Objectives: (1) To estimate the relative risk of stroke among various groups of professional drivers; (2) to determine if any excess risk should be attributed to infarction or haemorrhage; (3)...

Elevated Hip Fracture Risk in Type 1 Diabetic Patients

Patients with type 1 diabetes often have low bone mineral density, but epidemiological data on fracture risk are sparse and imprecise, particularly for men. In the Swedish Inpatient Register, we identified a population-based cohort of 24,605 patients (12,551 men and 12,054 women) who were hospitalized for diabetes before age 31 years during 1975 through 1998. Follow-up for hip fracture was accomplished through cross-linkage in the Inpatient Register until the end of 1998. Censoring information was obtained from the registers of Death and Migration. Using the Kaplan-Meier method, we calculated the cumulative probability of getting a hip fracture. Standardized hospitalization ratios and their 95% CIs estimated relative risks with the age-, sex-, and calendar period-matched Swedish general population as reference. In total, 70 and 51 first hip fractures were ascertained in men and women, respectively, corresponding to a cumulative probability (both sexes) of 65.8/1,000 until age 65 years. Markedly elevated risks were observed in both men and women (standardized hospitalization ratios = 7.6 [95% CI 5.9-9.6] and 9.8 [7.3-12.9], respectively), increasing with follow-up time. Ophthalmic, nephropathic, neurological, and cardiovascular complications were indicators of particularly high risks. Both male and female type 1 diabetic patients are at increased risk for hip fracture. Although optimal preventive measures still need to be defined, the co-occurrence with other diabetes complications suggests that tighter metabolic control might reduce the risk.

Hospitalized injuries among bridge and tunnel construction workers

The aim of the present study was to compare relative risks for hospitalizing injuries among 7761 Danish workers engaged in the construction of different types of major tunnel and bridge traffic links during 1991–2000 in order to determine construction types with high injury risk. Standardized hospitalization ratios (SHR) for injuries were calculated by type of construction (low‐level bridge, high‐level bridge, bored tunnel and submerged tunnel). All employed males in the total population of Denmark were used as the standard population. Neither the SHR nor the distribution of injury types were independent of the construction type (p<0.05). The hospitalization ratio was highest for bored tunnel workers (SHR = 1.91; 95% CI: 1.65–2.21) and here toxic gases and smoke were a major problem, whereas head injuries were more frequent among workers engaged in other types of construction. The substantial variation in SHR values with construction type might be an argument for inclusion of workers safety in pre‐project decision making.

Hospitalisations among seafarers on merchant ships

Aims: To study morbidity among active seafarers in the merchant navy in order to clarify possible work related morbidity and the morbidity related to work and lifestyle where possible preventive...

Hospitalizations among female home‐helpers in Denmark, 1981–1997

Occupational health problems among home-helpers have been reported in a series of studies, and the need for intervention has been pointed out. To facilitate decisions regarding interventions and to establish baseline values for future evaluation of preventive efforts, the present study aimed to elucidate the disease pattern among female home-helpers in Denmark. Cohorts of all 20-59-year-old Danish female home-helpers in the years 1981, 1986, 1991, and 1994 were formed, to calculate age standardized hospitalization ratios (SHR) and time trends (1981-1997) for a large variety of diagnostic aggregations. Significantly high SHRs were found for injuries, infectious and parasitic diseases, and for diseases of the nervous system, circulatory system, the respiratory organs, digestive system, and the musculoskeletal system. When adjusting for social group the SHRs for varicose veins, ischemic heart diseases (IHD), and musculoskeletal disorders were still significantly high while the SHR for malignant neoplasm of respiratory organs became significantly low. The time trends revealed increased relative risks for IHD and asthma, and a decreasing relative risk for duodenal ulcer. Employment in the Danish home-help sector is associated with an elevated hospitalization risk due to many work-related diseases.

Extent and sources of geographic variation in Medicare end-stage renal disease expenditures

Geographic variations in practices and expenditures have been widely documented, leading to concerns that care in some regions is clinically suboptimal and/or economically inefficient. Our objectives are to determine the extent and sources of geographic variation in Medicare expenditures per patient with end-stage renal disease (ESRD) per year. The study population included all patients with ESRD with Medicare as primary payer during 1997 (n = 284,670). Medicare expenditures were summarized at the hospital referral region (HRR) level. Using regression analysis, we estimated the relationship between expenditures and demographics, case mix, dialysis provider characteristics, distribution of patients across renal replacement therapy modalities, standardized hospitalization ratios, and healthcare wages. Spending per patient-year varied threefold across HRRs, ranging from $17,791 to $59,025 (mean, $38,966 ± $6,774 [SD]). The regression equation explained 80% of this variation. Although several demographic and case-mix indicators that have been related to spending at the individual level were statistically significant predictors of spending at the HRR level, they did not show enough geographic variation to explain a large fraction of spending variation. Rather, patient distributions across renal replacement modalities, hospitalization patterns, and healthcare wages were the most powerful predictors of spending. Compared with Medicare generally, both the mean and SD of ESRD expenditures were approximately seven times larger. The substantial geographic variability in expenditures for patients with ESRD indicates the potential for improving efficiency and quality of care. Interventions designed to increase transplantation rates, ensure access to peritoneal dialysis, and reduce hospitalization appear most promising. © 2001 by the National Kidney Foundation, Inc.

Evaluation of disease-state management of dialysis patients

Dialysis patients are the only Medicare beneficiaries prohibited from joining managed care plans. Concerns have been raised about the ability of such plans to provide the comprehensive care required by patients with this complex condition. However, more than 20,000 dialysis patients belong to such plans because they were enrolled before developing end-stage renal disease (ESRD). Disease-state management, successfully applied to patients with diabetes mellitus and congestive heart failure, Is now being used in patients with ESRD. Standardized mortality ratios (SMRs) and standardized hospitalization ratios (SHRs) were calculated for 1998 and 1999 In 1,541 patients enrolled in the RMS Disease Management program of renal disease-state management using US Renal Data System methods. SMRs were 0.643 and 0.806 for 1998 and 1999, respectively, significantly different from 1.0 for both years (P < 0.001). SHRs were 0.620 and 0.503 for 1998 and 1999, respectively, significantly different from 1.0 for both years (P < 0.001). Although additional studies are needed to define the aspects of care that are most Important for the outcomes seen, this study shows that favorable outcomes are achievable for this vulnerable patient population within a managed care setting that applies coordinated approaches to care.

Agricultural work and the risk of Parkinson's disease in Denmark, 1981-1993.

This study examined the possible association between agricultural and horticultural work and the subsequent morbidity of Parkinson's disease. Fixed cohorts of 2,273,872 men and women aged 20-59 years on 1 January 1981 and identified in the Central Population Register of Denmark were followed, and all first-time hospitalizations with Parkinson's disease as the principal diagnosis during the 13 years until 31 December 1993 were recorded. Standardized hospitalization ratios (SHR) were calculated using all gainfully employed persons as the standard and by multiplying the ratio by 100. Ninety-five percent confidence intervals (95% CI) were calculated on the assumption of a Poisson distribution. A high risk of Parkinson's disease was found for the men and women in agriculture and horticulture (134 cases, SHR 132, 95% CI 111-156). Statistically significantly high risks were found for farmers (79 cases, SHR 130, 95% CI 103-163) and for all men in agriculture and horticulture (109 cases, SHR 134, 95% CI 109-162). A consistent pattern of high Parkinson's disease morbidity was found among occupational groups employed in agriculture and horticulture.

Social and occupational differences in chronic obstructive lung disease in Denmark 1981-1993

Chronic obstructive pulmonary disease (COPD) is a common crippling disorder related to exposure to noxious dust and fumes. The purpose of this study was to estimate relative rates of COPD in socioeconomic groups and in 'classic' high-risk industries. Cohorts of all gainfully employed 20-59 year old Danes in the years 1981, 1986, and 1991 were formed, to compare standardized hospitalization ratios (SHR) and time trends (1981-93). The risk ratio (RR) between unskilled workers and senior salaried staff was 2.31, (95% CI 2.13-2.51) for men and 1.62 (1.38-1.92) for women. Among classic high-risk occupations we found a decreasing SHR in farmers and an increasing SHR in the hotel and restaurant industry and for taxi and bus drivers. The study confirmed earlier reports on high risks in the metal, rubber, and bakery industries. Apart from the reduced SHR among farmers there were no signs of decreasing differences in COPD risk.

Stroke morbidity in professional drivers in Denmark 1981-1990.

Little has been published on the possible associations between professional driving and stroke although it is well documented from several countries that professional drivers have an increased risk of coronary heart disease. There are common aetiologic factors for coronary heart disease and stroke. The aim of the present study is to estimate the risk of stroke among professional drivers in 13 male and 4 female groups defined by employment status and industry. Cohorts of all gainfully employed 20-59 year old Danes were formed to compare Standardized Hospitalization Ratios (SHR) for stroke between occupational groups. The follow-up period was 10 years. A consistent pattern of high risk was found for all groups of male drivers except removal men. The group 'All drivers' had an increased risk of stroke SHR = 130 for men (95% confidence interval [CI]: 123.6-137.5) and SHR = 148 for women (95% CI: 113.9-191.4). Standardization for employment status reduced the risks but they were still found to be statistically significantly increased: SHR = 114 for men (95% CI: 108.2-120.4) and SHR = 130 for women (95% CI: 100.0-168.0). Professional driving is associated with an increased risk of stroke morbidity.

Referral bias among health workers in studies using hospitalization as a proxy measure of the underlying incidence rate.

Contacts with health services like hospitals or general practitioners are usually the only available proxy measure of incidence of disease in studies based on secondary data and differential referrals or care-seeking behavior often bias such proxy measures. In former analyses based on the Occupational Hospitalization Register in Denmark assisting nurses had high Standardized Hospitalization Ratios for many diseases. It was, however, suspected that it fully or partly was due to a referral bias or self-selection to hospital treatment rather than exposures to occupational hazards. The aim of the present study is to evaluate the referral bias hypothesis by comparing hospitalization and mortality data for health workers for a disease category with a high mortality. Cohorts of all gainfully employed 20- to 59-year-old Danes were formed in order to compare Standardized Mortality Ratios and Standardized Hospitalization Ratios of ischemic heart disease (IHD) in occupational groups. The follow-up period was 10 years. For most of the investigated occupational groups a similar disease pattern was found whether hospitalization or death was used as the outcome measure. In "nurse assistants" a statistically significant higher risk was, however, found using hospitalization due to IHD as the end point rather than mortality. Additional analysis did not support the hypothesis that the finding could be explained by differentiated hospitalization due to social factors. The true incidence rates of the disease need not be equally well described by proxy measures such as hospitalization diagnosis or death diagnosis in all occupational groups. Differential access to medical treatment in some groups may lead to bias when hospital data are used as proxy measures for the underlying incidence rates.

Occupation, employment status and chronic inflammatory bowel disease in Denmark.

Certain occupational groups have formerly been identified as having higher risks of suffering from chronic inflammatory bowel diseases. These were evaluated in an independent data set. A cohort, comprising all 2 273 872 male and female Danes aged 20-59 years on 1 January 1986 were followed up for hospitalizations due to chronic inflammatory bowel disease until 31 December 1990. From 1981 to 1990 6296 first time admissions occurred. The incidence increased from 1981-1985 to 1986-1990. Of 363 male and 213 female occupational groups eight and five groups respectively had statistically significant raised standardized hospitalization ratios. Among 15 groups previously found to have significant odds ratios only female office staff and health occupations were found to have statistically significant raised standardized hospitalization ratios. Ratios for occupational groups with non-daytime work were not statistically significant. Compared to occupations without sedentary work occupations with predominantly sedentary work had a standardized hospitalization ratio of 125 (95% confidence interval [95% CI] : 116.9-133.1). Self-employed had low hospitalization rates, while 'other salaried staff' and 'not economically active' had high rates. We found no consistent pattern of occupations at increased risk except that sedentary work may increase the risk of attracting chronic inflammatory bowel disease.