Association of nurse staffing and unit occupancy with mortality and morbidity among very preterm infants: a multicentre study.

OBJECTIVE: In a healthcare system with finite resources, hospital organisational factors may contribute to patient outcomes. We aimed to assess the association of nurse staffing and neonatal intensive care unit (NICU) occupancy with outcomes of preterm infants born <33 weeks' gestation. DESIGN: Retrospective cohort study. SETTING: Four level III NICUs. PATIENTS: Infants born 23-32 weeks' gestation 2015-2018. MAIN OUTCOME MEASURES: Nursing provision ratios (nursing hours worked/recommended nursing hours based on patient acuity categories) and unit occupancy rates were averaged for the first shift, 24 hours and 7 days of admission of each infant. Primary outcome was mortality/morbidity (bronchopulmonary dysplasia, severe neurological injury, retinopathy of prematurity, necrotising enterocolitis and nosocomial infection). ORs for association of exposure with outcomes were estimated using generalised linear mixed models adjusted for confounders. RESULTS: Among 1870 included infants, 823 (44%) had mortality/morbidity. Median nursing provision ratio was 1.03 (IQR 0.89-1.22) and median unit occupancy was 89% (IQR 82-94). In the first 24 hours of admission, higher nursing provision ratio was associated with lower odds of mortality/morbidity (OR 0.93, 95% CI 0.89 to 0.98), and higher unit occupancy was associated with higher odds of mortality/morbidity (OR 1.19, 95% CI 1.04 to 1.36). In causal mediation analysis, nursing provision ratios mediated 47% of the association between occupancy and outcomes. CONCLUSIONS: NICU occupancy is associated with mortality/morbidity among very preterm infants and may reflect lack of adequate resources in periods of high activity. Interventions aimed at reducing occupancy and maintaining adequate resources need to be considered as strategies to improve patient outcomes.

Associations between patient factors and adverse events in the home care setting: a secondary data analysis of two canadian adverse event studies.

BACKGROUND: Early identification of patients at who have a higher risk for the occurrence of harm can provide patient safety improvement opportunities. Patient factors contribute to adverse event occurrence. The study aim was to identify a single, parsimonious model of home care patient factors that, regardless of location and differences in home care program management and design factors, could provide a means of locating patients at higher and lower risk of harm. METHODS: Split modeling using secondary analyses of data from two recent Canadian home care patient safety studies was undertaken. Patient factors from the Minimum Data Set Resident Assessment Instrument (RAI) for Home Care and diagnoses consistent with ICD-10 and RAI-Mental Health assessment were used. Continuous and categorical measures of factors were considered. Adverse events were defined using World Health Organization taxonomy and measured on a dichotomous yes/no scale. Patient factors significantly associated (Pearson's Chi Square, p ≤ .05) with the occurrence of adverse events in both earlier studies were entered in forward selection regression analyses to locate factors predictive of adverse event occurrence. RESULTS: Instrumental activities of daily living dependency and escalating co-morbidity counts are associated with patient vulnerability to adverse events. CONCLUSIONS: Instrumental activities of daily living dependency and burden of illness, both easily identifiable early in the episode of care, are significantly associated with the risk of adverse event occurrence, however there is regional variability in the relationships.

Adverse events associated with hospitalization or detected through the RAI-HC assessment among Canadian home care clients.

BACKGROUND: The occurrence of adverse events (AEs) in care settings is a patient safety concern that has significant consequences across healthcare systems. Patient safety problems have been well documented in acute care settings; however, similar data for clients in home care (HC) settings in Canada are limited. The purpose of this Canadian study was to investigate AEs in HC, specifically those associated with hospitalization or detected through the Resident Assessment Instrument for Home Care (RAI-HC). METHOD: A retrospective cohort design was used. The cohort consisted of HC clients from the provinces of Nova Scotia, Ontario, British Columbia and the Winnipeg Regional Health Authority. RESULTS: The overall incidence rate of AEs associated with hospitalization ranged from 6% to 9%. The incidence rate of AEs determined from the RAI-HC was 4%. Injurious falls, injuries from other than fall and medication-related events were the most frequent AEs associated with hospitalization, whereas new caregiver distress was the most frequent AE identified through the RAI-HC. CONCLUSION: The incidence of AEs from all sources of data ranged from 4% to 9%. More resources are needed to target strategies for addressing safety risks in HC in a broader context. Tools such as the RAI-HC and its Clinical Assessment Protocols, already available in Canada, could be very useful in the assessment and management of HC clients who are at safety risk.

Assessing adverse events among home care clients in three Canadian provinces using chart review.

OBJECTIVES: The objectives of this study were to document the incidence rate and types of adverse events (AEs) among home care (HC) clients in Canada; identify factors contributing to these AEs; and determine to what extent evidence of completion of incident reports were documented in charts where AEs were found. METHODS: This was a retrospective cohort study based on expert chart review of a random sample of 1200 charts of clients discharged in fiscal year 2009-2010 from publicly funded HC programmes in Manitoba, Quebec and Nova Scotia, Canada. RESULTS: The results show that 4.2% (95% CI 3.0% to 5.4%) of HC patients discharged in a 12-month period experienced an AE. Adjusting to account for clients with lengths of stay in HC of less than 1 year, the AE incidence rate per client-year was 10.1% (95% CI 8.4% to 11.8%); 56% of AEs were judged preventable. The most frequent AEs were injuries from falls, wound infections, psychosocial, behavioural or mental health problems and adverse outcomes from medication errors. More comorbid conditions (OR 1.15; 95% CI 1.05 to 1.26) and a lower instrumental activities of daily living score (OR 1.54; 95% CI 1.16 to 2.04) were associated with a higher risk of experiencing an AE. Clients' decisions or actions contributed to 48.4% of AEs, informal caregivers 20.4% of AEs, and healthcare personnel 46.2% of AEs. Only 17.3% of charts with an AE contained documentation that indicated an incident report was completed, while 4.8% of charts without an AE had such documentation. CONCLUSIONS: Client safety is an important issue in HC, as it is in institutionalised care. HC includes the planned delivery of self-care by clients and care provision by family, friends and other individuals often described as 'informal' caregivers. As clients and these caregivers can contribute to the occurrence of AEs, their involvement in the delivery of healthcare interventions at home must be considered when planning strategies to improve HC safety.

Polypharmacy meets polyherbacy: pharmaceutical, over-the-counter, and natural health product use among Canadian adults.

OBJECTIVES: Natural health products (NHP) are increasingly being used to supplement prescription medications (PM) and over-the-counter (OTC) products. The objective of this study was to examine patterns of overall health product use and how these patterns are associated with social and health factors. METHODS: We used direct health measures data from the Canada Health Measures Survey (CHMS) Cycle 1.0 (2007/2009) to examine recent product use among adults aged 18-79 years (n=3,721). Latent class analyses were used to detect use (propensity) and intensity of use among users of all three product types. Associations between social and health covariates and product patterns were examined using linear and multinomial logit regression procedures. RESULTS: Three latent classes of health product use were identified. The largest (43%) was characterized by a high probability of PM and NHP but not OTC use. Class two (37%), in contrast, had a low probability of using any of the three health products. Class three (20%) had a high probability of PM and OTC but not NHP use. Age, gender, immigrant status, household size, co-morbidity, perceived health status, and having a regular doctor were associated with these patterns of use. Analyses of intensity of product use among users revealed seven distinct classes; these were differentiated by age, household size, co-morbidity and weight (BMI status). CONCLUSION: If defining polypharmacy or polyherbacy is based simply on number of health products used, then for Canadians under age 80 neither practice appeared to be widespread. More work needs to be done to define the "poly" in polypharmacy and polyherbacy. This will inform the conversation on appropriate product use, particularly given that about one half of Canadians used medications and NHPs concurrently.

Adverse events among Ontario home care clients associated with emergency room visit or hospitalization: a retrospective cohort study.

BACKGROUND: Home care (HC) is a critical component of the ongoing restructuring of healthcare in Canada. It impacts three dimensions of healthcare delivery: primary healthcare, chronic disease management, and aging at home strategies. The purpose of our study is to investigate a significant safety dimension of HC, the occurrence of adverse events and their related outcomes. The study reports on the incidence of HC adverse events, the magnitude of the events, the types of events that occur, and the consequences experienced by HC clients in the province of Ontario. METHODS: A retrospective cohort design was used, utilizing comprehensive secondary databases available for Ontario HC clients from the years 2008 and 2009. The data were derived from the Canadian Home Care Reporting System, the Hospital Discharge Abstract Database, the National Ambulatory Care Reporting System, the Ontario Mental Health Reporting System, and the Continuing Care Reporting System. Descriptive analysis was used to identify the type and frequency of the adverse events recorded and the consequences of the events. Logistic regression analysis was used to examine the association between the events and their consequences. RESULTS: The study found that the incident rate for adverse events for the HC clients included in the cohort was 13%. The most frequent adverse events identified in the databases were injurious falls, injuries from other than a fall, and medication-related incidents. With respect to outcomes, we determined that an injurious fall was associated with a significant increase in the odds of a client requiring long-term-care facility admission and of client death. We further determined that three types of events, delirium, sepsis, and medication-related incidents were associated directly with an increase in the odds of client death. CONCLUSIONS: Our study concludes that 13% of clients in homecare experience an adverse event annually. We also determined that an injurious fall was the most frequent of the adverse events and was associated with increased admission to long-term care or death. We recommend the use of tools that are presently available in Canada, such as the Resident Assessment Instrument and its Clinical Assessment Protocols, for assessing and mitigating the risk of an adverse event occurring.

Associations of patient safety outcomes with models of nursing care organization at unit level in hospitals.

OBJECTIVE: To examine the associations of four distinct nursing care organizational models with patient safety outcomes. DESIGN: Cross-sectional correlational study. Using a standardized protocol, patients' records were screened retrospectively to detect occurrences of patient safety-related events. Binary logistic regression was used to assess the associations of those events with four nursing care organizational models. SETTING: Twenty-two medical units in 11 hospitals in Quebec, Canada, were clustered into 4 nursing care organizational models: 2 professional models and 2 functional models. PARTICIPANTS: Two thousand six hundred and ninety-nine were patients hospitalized for at least 48 h on the selected units. MAIN OUTCOME MEASURE: Composite of six safety-related events widely-considered sensitive to nursing care: medication administration errors, falls, pneumonia, urinary tract infection, unjustified restraints and pressure ulcers. Events were ultimately sorted into two categories: events 'without major' consequences for patients and events 'with' consequences. RESULTS: After controlling for patient characteristics, patient risk of experiencing one or more events (of any severity) and of experiencing an event with consequences was significantly lower, by factors of 25-52%, in both professional models than in the functional models. Event rates for both functional models were statistically indistinguishable from each other. CONCLUSIONS: Data suggest that nursing care organizational models characterized by contrasting staffing, work environment and innovation characteristics may be associated with differential risk for hospitalized patients. The two professional models, which draw mainly on registered nurses (RNs) to deliver nursing services and reflect stronger support for nurses' professional practice, were associated with lower risks than are the two functional models.

Identification of safety outcomes for Canadian home care clients: evidence from the resident assessment instrument--home care reporting system concerning emergency room visits.

Problems of patient safety have been well documented in hospitals. However, we have very limited data about patient safety problems among home care clients. The purpose of this study was to assess the burden of safety problems among Canadian home care clients using data collected through the Resident Assessment Instrument - Home Care (RAI HC), and to explore the role of age and patient safety risk factors in explaining variations in adverse outcomes, with a particular focus on emergency room visits. The study methodology involved a secondary analysis of data collected through the Canadian Home Care Reporting System. The study sample consisted of all home care clients who qualified to receive an RAI HC assessment from Ontario, Nova Scotia and Winnipeg Regional Health Authority for the 2003-2007 reporting period. There were a total of 30,396 cases with a paired intake and 12-month follow-up assessment available for analysis. New falls, unintended weight loss, new emergency room (ER) visits and new hospital visits were the most prevalent adverse outcomes. A history of falls, a cancer diagnosis, polypharmacy, receiving an anxiolytic medication and receiving an antidepressant medication were associated with an increased risk of ER visits, while low self reliance and limitation in activities of living were associated with a decreased risk of ER visits. Understanding clients'risk profiles is foundational to effective patient care.

The nature of safety problems among Canadian homecare clients: evidence from the RAI-HC reporting system.

AIM(S): The purpose of this study was to identify the nature of patient safety problems among Canadian homecare (HC) clients, using data collected through the RAI-HC((c)) assessment instrument. BACKGROUND: Problems of patient safety have been well documented in hospitals. However, we have very limited data about patient safety problems among HC clients. METHOD(S): The study methodology involved a secondary analysis of data collected through the Canadian home care reporting system. The study sample consisted of all HC clients who qualified to receive a RAI-HC assessment from Ontario, Nova Scotia and Winnipeg Regional Health Authority for the 2003-2007 reporting period. There were a total of 238 958 cases available for analysis; 205 953 from Ontario, 26 751 from Nova Scotia and 6254 from Winnipeg Regional Health Authority. RESULTS: New fall (11%), unintended weight loss (9%), new emergency room (ER) visits (7%) and new hospital visits (8%) were the most prevalent potential adverse events identified in our study. A small proportion of the HC clients experienced a new urinary tract infection (2%). CONCLUSION(S): Understanding clients' risk profiles is foundational to effective patient care management. IMPLICATIONS FOR NURSING MANAGEMENT: We need to begin to develop evidence about best practices for ameliorating safety risk.

Impact of patient communication problems on the risk of preventable adverse events in acute care settings.

BACKGROUND: Up to 50% of adverse events that occur in hospitals are preventable. Language barriers and disabilities that affect communication have been shown to decrease quality of care. We sought to assess whether communication problems are associated with an increased risk of preventable adverse events. METHODS: We randomly selected 20 general hospitals in the province of Quebec with at least 1500 annual admissions. Of the 145,672 admissions to the selected hospitals in 2000/01, we randomly selected and reviewed 2355 charts of patients aged 18 years or older. Reviewers abstracted patient characteristics, including communication problems, and details of hospital admission, and assessed the cause and preventability of identified adverse events. The primary outcome was adverse events. RESULTS: Of 217 adverse events, 63 (29%) were judged to be preventable, for an overall population rate of 2.7% (95% confidence interval [CI] 2.1%-3.4%). We found that patients with preventable adverse events were significantly more likely than those without such events to have a communication problem (odds ratio [OR] 3.00; 95% CI 1.43-6.27) or a psychiatric disorder (OR 2.35; 95% CI 1.09-5.05). Patients who were admitted urgently were significantly more likely than patients whose admissions were elective to experience an event (OR 1.64, 95% CI 1.07-2.52). Preventable adverse events were mainly due to drug errors (40%) or poor clinical management (32%). We found that patients with communication problems were more likely than patients without these problems to experience multiple preventable adverse events (46% v. 20%; p = 0.05). INTERPRETATION: Patients with communication problems appeared to be at highest risk for preventable adverse events. Interventions to reduce the risk for these patients need to be developed and evaluated.

Avaliação do índice de comorbidade de Charlson em internações da região de Ribeirão Preto, São Paulo, Brasil / Evaluation of the Charlson comorbidity index among inpatients in Ribeirão Preto, São Paulo State, Brazil

O objetivo deste artigo foi avaliar o uso do índice de comorbidade de Charlson (ICC) para predizer óbito hospitalar em internações da região de Ribeirão Preto, São Paulo, Brasil. Foram analisadas 54.680 hospitalizações entre janeiro de 1996 e dezembro de 1997. Duas adaptações do ICC para a Classificação Internacional de Doenças (CID) foram comparadas e as trinta condições clínicas avaliadas por Charlson foram revistas. A regressão logística foi utilizada para avaliar a capacidade dos modelos de predizer o óbito hospitalar. O modelo de base incluiu: idade, sexo e diagnóstico principal. Diferenças na adaptação para a CID-9 pouco impactaram a capacidade de discriminação dos modelos. A revisão das trinta condições clínicas aumentou a capacidade de discriminação do modelo de predição de óbito (estatística C = 0,73) quando comparado ao modelo com o ICC original (estatística C = 0,72). Todos os modelos testados tiveram efeito reduzido sobre a capacidade discriminativa do modelo de base (estatística C = 0,70). Os resultados apontam a importância de se dispor no país de um sistema de informação que permita uma descrição completa da morbidade hospitalar para o monitoramento do desempenho dos serviços.

The objective of this article was to evaluate the use of the Charlson comorbidity index (CCI) to predict inpatient death in Ribeirão Preto, São Paulo State, Brazil. 54,680 hospitalizations from January 1996 to December of 1997 were analyzed. Two International Classification of Diseases adaptations of CCI were compared, and the 30 clinical conditions assessed by the Charlson index were reviewed. Logistic regression was used to evaluate the models' capacity to predict inpatient death. The baseline model included: age, sex, and principal diagnosis. Differences in ICD adaptations showed little effect on the models' discriminatory capacity. Revision of the 30 clinical conditions increased the model's discriminatory capacity to predict death (C statistic = 0.73), as compared to the model with the original CCI (C statistic = 0.72). All tested models had a reduced effect on the baseline model's discriminatory capacity (C statistic = 0.70). The results show the importance of Brazil having an information system that allows a complete description of hospital morbidity in order to monitor health service performance.

Predictors of mental health service utilization by people using resources for homeless people in Canada.

OBJECTIVE: This study used Pescosolido's network episode model to examine mental health service utilization among impoverished people accessing resources for the homeless in Canada's universal health care setting. METHODS: The sample consisted of 439 people who met DSM-IV criteria for affective or psychotic disorders who were assessed as part of a larger study of resources for homeless or impoverished people in Montreal and Quebec City. Interviews were organized into the framework of four network episode model concepts: sociodemographic characteristics, illness characteristics, illness history, and social network. These blocks of variables were then analyzed in terms of their accuracy in predicting mental health service utilization. RESULTS: Eighty-four percent of the sample were male, the mean+/-SD age was 41+/-12 years, and 36% were homeless at the time of the interview, but nearly half (48%) of the population had been homeless previously. The research shows that each network episode model concept except illness history significantly predicted utilization of mental health services. Female gender, youth, never being homeless (sociodemographic characteristics), presence of antisocial personality disorders within the preceding year, past or current alcohol-related disorders (illness characteristics), hospitalization before the preceding year (illness history), and a larger social support network were related to utilization of mental health services. CONCLUSIONS: In the absence of economic barriers to health care, there are other significant barriers to the use of mental health services for people who live in poverty. A better understanding of these factors will help in meeting the service needs of impoverished mentally ill people.

Practice patterns of physiotherapists in the treatment of work-related back pain.

RATIONALE AND OBJECTIVES: Although physiotherapists (PTs) are one of the health professionals most involved in the treatment of back pain, their practice patterns have not been well studied. The study objectives were to identify the practice patterns of PTs treating workers suffering from acute/subacute back pain, with and without radiating pain below the knee, and to assess the relationship between these patterns and characteristics of PTs. METHODS: PTs working in private clinics in the province of Quebec, Canada were invited to participate. Each PT used a self-administered questionnaire to record, for each treatment session, treatment objectives, interventions used and education given to two workers with back pain, one without radiating pain (n = 189 PTs) and one with radiating pain (n = 136 PTs). Multiple correspondence analysis with hierarchical classification was used to identify practice patterns of PTs. Multinomial logistic regressions were used to assess the relationship between practice patterns and PTs characteristics. RESULTS: For workers without radiating pain, 51.9% of PTs focused their treatment on soft tissue mobilizations/massage and heat, 24.3% focused on the McKenzie approach and related interventions, and 23.8% focused on exercises and function. Similar results were found for workers with radiating pain. Most of the PT characteristics were not related to practice patterns. CONCLUSIONS: The practices of PTs appeared to be separated into three distinct patterns. These practice variations suggest that there may be disagreement or uncertainty among PTs in the management of work-related back pain. The lack of evidence for the majority of interventions used by PTs and the difficulties of integrating evidence into clinical practice may be possible explanations.

The Canadian Adverse Events Study: the incidence of adverse events among hospital patients in Canada.

BACKGROUND: Research into adverse events (AEs) has highlighted the need to improve patient safety. AEs are unintended injuries or complications resulting in death, disability or prolonged hospital stay that arise from health care management. We estimated the incidence of AEs among patients in Canadian acute care hospitals. METHODS: We randomly selected 1 teaching, 1 large community and 2 small community hospitals in each of 5 provinces (British Columbia, Alberta, Ontario, Quebec and Nova Scotia) and reviewed a random sample of charts for nonpsychiatric, nonobstetric adult patients in each hospital for the fiscal year 2000. Trained reviewers screened all eligible charts, and physicians reviewed the positively screened charts to identify AEs and determine their preventability. RESULTS: At least 1 screening criterion was identified in 1527 (40.8%) of 3745 charts. The physician reviewers identified AEs in 255 of the charts. After adjustment for the sampling strategy, the AE rate was 7.5 per 100 hospital admissions (95% confidence interval [CI] 5.7- 9.3). Among the patients with AEs, events judged to be preventable occurred in 36.9% (95% CI 32.0%-41.8%) and death in 20.8% (95% CI 7.8%-33.8%). Physician reviewers estimated that 1521 additional hospital days were associated with AEs. Although men and women experienced equal rates of AEs, patients who had AEs were significantly older than those who did not (mean age [and standard deviation] 64.9 [16.7] v. 62.0 [18.4] years; p = 0.016). INTERPRETATION: The overall incidence rate of AEs of 7.5% in our study suggests that, of the almost 2.5 million annual hospital admissions in Canada similar to the type studied, about 185 000 are associated with an AE and close to 70 000 of these are potentially preventable.

Mortalidade hospitalar e tempo de permanência: comparação entre hospitais públicos e privados na região de Ribeirão Preto, São Paulo, Brasil / Hospital mortality and length of stay: comparison between public and private hospitals in Ribeirão Preto, São Paulo State, Brazil

A avaliação de desempenho dos serviços de saúde é essencial. A comparação de indicadores de desempenho requer o uso de estratégias de ajuste de risco. O objetivo deste artigo é avaliar variações no desempenho clínico, mensurado pela mortalidade e pelo tempo de permanência, entre hospitais públicos e privados, levando em conta diferenças nas características dos pacientes tratados. Este estudo é limitado à região de Ribeirão Preto, São Paulo, Brasil. Entre os anos de 1996 e 1998, 32.906 pacientes admitidos com diagnósticos cardiovasculares e respiratórios foram estudados. As variáveis usadas para o ajuste de risco dos indicadores de desempenho foram: sexo, idade, diagnóstico principal e medidas de gravidade baseada em comorbidade. Os resultados mostraram que o desempenho clínico dos hospitais públicos, mensurado pela mortalidade hospitalar ajustada (razão de chance = 0,41), é superior ao dos privados. Os hospitais públicos e privados não foram estatisticamente diferentes com relação ao tempo de permanência dos pacientes. Ainda que problemas conceituais e metodológicos devam ser resolvidos, taxa de mortalidade e outros indicadores de desempenho ajustados devem ser considerados como instrumentos úteis para identificar problemas de desempenho dos serviços de saúde.

Probabilistic linkage in household survey on hospital care usage

OBJECTIVE: To evaluate the potential advantages and limitations of the use of the Brazilian hospital admission authorization forms database and the probabilistic record linkage methodology for the validation of reported utilization of hospital care services in household surveys. METHODS: A total of 2,288 households interviews were conducted in the county of Duque de Caxias, Brazil. Information on the occurrence of at least one hospital admission in the year preceding the interview was obtained from a total of 10,733 household members. The 130 records of household members who reported at least one hospital admission in a public hospital were linked to a hospital database with 801,587 records, using an automatic probabilistic approach combined with an extensive clerical review. RESULTS: Seventy-four (57 percent) of the 130 household members were identified in the hospital database. Yet only 60 subjects (46 percent) showed a record of hospitalization in the hospital database in the study period. Hospital admissions due to a surgery procedure were significantly more likely to have been identified in the hospital database. The low level of concordance seen in the study can be explained by the following factors: errors in the linkage process; a telescoping effect; and an incomplete record in the hospital database. CONCLUSIONS: The use of hospital administrative databases and probabilistic linkage methodology may represent a methodological alternative for the validation of reported utilization of health care services, but some strategies should be employed in order to minimize the problems related to the use of this methodology in non-ideal conditions. Ideally, a single identifier, such as a personal health insurance number, and the universal coverage of the database would be desirable

Probabilistic linkage in household survey on hospital care usage.

OBJECTIVE: To evaluate the potential advantages and limitations of the use of the Brazilian hospital admission authorization forms database and the probabilistic record linkage methodology for the validation of reported utilization of hospital care services in household surveys. METHODS: A total of 2,288 households interviews were conducted in the county of Duque de Caxias, Brazil. Information on the occurrence of at least one hospital admission in the year preceding the interview was obtained from a total of 10,733 household members. The 130 records of household members who reported at least one hospital admission in a public hospital were linked to a hospital database with 801,587 records, using an automatic probabilistic approach combined with an extensive clerical review. RESULTS: Seventy-four (57%) of the 130 household members were identified in the hospital database. Yet only 60 subjects (46%) showed a record of hospitalization in the hospital database in the study period. Hospital admissions due to a surgery procedure were significantly more likely to have been identified in the hospital database. The low level of concordance seen in the study can be explained by the following factors: errors in the linkage process; a telescoping effect; and an incomplete record in the hospital database. CONCLUSIONS: The use of hospital administrative databases and probabilistic linkage methodology may represent a methodological alternative for the validation of reported utilization of health care services, but some strategies should be employed in order to minimize the problems related to the use of this methodology in non-ideal conditions. Ideally, a single identifier, such as a personal health insurance number, and the universal coverage of the database would be desirable.