Rebbecca Lilley

Prospective outcomes of injury study

Background: In New Zealand (NZ), 20% of adults report a disability, of which one-third is caused by injury. No prospective epidemiological studies of predictors of disability following all-cause injury among New Zealanders have been undertaken. Internationally, studies have focused on a limited range of predictors or specific injuries. Although these studies provide useful insights, applicability to NZ is limited given the importance of NZ’s unique macro-social factors, such as NZ’s no-fault accident compensation and rehabilitation scheme, the Accident Compensation Corporation (ACC). Objectives: (1) To quantitatively determine the injury, rehabilitation, personal, social and economic factors leading to disability outcomes following injury in NZ. (2) To qualitatively explore experiences and perceptions of injury-related outcomes in face-to-face interviews with 15 Māori and 15 other New Zealanders, 6 and 12 months after injury. Setting: Four geographical regions within NZ. Design: Prospective cohort study with telephone interviews 1, 4 and 12 months after injury. Participants: 2500 people (including 460 Māori), aged 18–64 years, randomly selected from ACC’s entitlement claims register (people likely to be off work for at least 1 week or equivalent). Data: Telephone interviews, electronic hospital and ACC injury data. Exposures include demographic, social, economic, work-related, health status, participation and/or environmental factors. Outcome measures: Primary: disability (including WHODAS II) and health-related quality of life (including EQ-5D). Secondary: participation (paid and unpaid activities), life satisfaction and costs. Analysis: Separate regression models will be developed for each of the outcomes. Repeated measures outcomes will be modelled using general estimating equation models and generalised linear mixed models.

Prospective Outcomes of Injury Study: recruitment, and participant characteristics, health and disability status

The Prospective Outcomes of Injury Study aims to identify predictors of disability following injury. Participants were selected from the entitlement claims register of New Zealands no-fault compensation insurer, the Accident Compensation Corporation, and followed up by interview for 2 years. This report describes changes to intended Prospective Outcomes of Injury Study methods and key characteristics of the cohort, with an emphasis on general health and disability before injury and soon afterwards. There were 2856 injured participants in the first interview, which occurred 3.2 months (median) after injury. The recruitment period was extended to enable inclusion of sufficient Māori participants. At the first interview, most participants were experiencing worse health status and increased disability compared to before injury, despite less than one-third reporting admission to hospital because of their injury. Analysis of outcome predictors related to post-injury function, disability and return-to-work soon after injury and 1 year later is now under way.

Prevalence and predictors of sub-acute phase disability after injury among hospitalised and non-hospitalised groups: a longitudinal cohort study

Introduction To reduce the burden on injury survivors and their supporters, factors associated with poor outcomes need to be identified so that timely post-injury interventions can be implemented. To date, few studies have investigated outcomes for both those who were hospitalised and those who were not. Aim To describe the prevalence and to identify pre-injury and injury-related predictors of disability among hospitalised and non-hospitalised people, three months after injury. Methods Participants in the Prospective Outcomes of Injury Study were aged 18–64 years and on an injury entitlement claims register with New Zealands no-fault injury compensation insurer, following referral by healthcare professionals. A wide range of pre-injury demographic, health and injury-related characteristics were collected at interview. Participants were categorised as ‘hospitalised’ if they were placed on New Zealands National Minimum Data Set within seven days of the injury event. Injury severity scores (NISS) and 12 injury categories were derived from ICD-10 codes. WHODAS assessed disability. Multivariable analyses examined relationships between explanatory variables and disability. Results Of 2856 participants, 2752 (96%) had WHODAS scores available for multivariable analysis; 673 were hospitalised; 2079 were not. Disability was highly prevalent among hospitalised (53.6%) and non-hospitalised (39.4%) participants, three-months after injury. In both groups, pre-injury disability, obesity and higher injury severity were associated with increased odds of post-injury disability. A range of other factors were associated with disability in only one group: e.g. female, ≥2 chronic conditions and leg fracture among hospitalised; aged 35–54 years, trouble accessing healthcare, spine or lower extremity sprains/dislocations and assault among non-hospitalised. Significance Disability was highly prevalent among both groups yet, with a few exceptions, factors associated with disability were not common to both groups. Where possible, including a range of injured people in studies, hospitalised and not, will increase understanding of the burden of disability in the sub-acute phase.

Factors predicting work status 3 months after injury: results from the Prospective Outcomes of Injury Study.

Objective Few studies examine predictors of work status following injury beyond injuries presenting to a hospital or emergency department. This paper examines the combined influences of socio-demographic, occupational, injury and pre-existing health and lifestyle factors as predictors of work status 3 months after hospitalised and non-hospitalised injury in a cohort of injured New Zealand workers. Design Prospective cohort study. Setting The Prospective Outcomes of Injury Study, New Zealand. Participants 2626 workforce active participants were identified from the Prospective Outcomes of Injury Study; 11 participants with missing outcome responses were excluded. Primary and secondary outcome measures The primary outcome of interest was ‘not working’ at the time of interview. Results 720 (27%) reported ‘not working’ 3 months after injury. The most important pre-injury predictors of not working following injury found by multidimensional modelling were as follows: low or unknown income, financial insecurity, physical work tasks, temporary employment, long week schedules, obesity, perceived threat to life and hospital admission. Contrary to expectations, workers reporting less frequent exercise pre-injury had lower odds of work absence. Pre-injury psychosocial and health factors were not associated with not working. Conclusion Certain pre-injury socio-demographic, physical work, work organisation, lifestyle and injury-related factors were associated with not working 3 months after injury. If these findings are confirmed, intervention strategies aimed at improving return to work should address multiple dimensions of both the worker and the workplace.

Prevalence and predictors of disability 24-months after injury for hospitalised and non-hospitalised participants: results from a longitudinal cohort study in New Zealand.

Introduction Most studies investigating disability outcomes following injury have examined hospitalised patients. It is not known whether variables associated with disability outcomes are similar for injured people who are not hospitalised. Aims This paper compares the prevalence of disability 24 months after injury for participants in the Prospective Outcomes of Injury Study who were hospitalised and those non-hospitalised, and also seeks to identify pre-injury and injury-related predictors of disability among hospitalised and non-hospitalised participants. Methods Participants, aged 18–64 years, were recruited from an injury claims register managed by New Zealand’s no-fault injury compensation insurer after referral by health care professionals. A wide range of pre-injury socio-demographic, health and psychosocial characteristics were collected, as well as injury-related characteristics; outcome is assessed using the WHODAS. Multivariable models estimating relative risks of disability for hospitalised and non-hospitalised participants were developed using Poisson regression methods. Results Of 2856 participants, analyses were restricted to 2184 (76%) participants for whom both pre-injury and 24 month WHODAS data were available. Of these, 25% were hospitalised. In both hospitalised and non-hospitalised groups, 13% experience disability (WHODAS≥10) 24 months after injury; higher than pre-injury (5%). Of 28 predictor variables, seven independently placed injured participants in the hospitalised group at increased risk of disability 24 months after injury; eight in the non-hospitalised. Only four predictors (pre-injury disability, two or more pre-injury chronic conditions, pre-injury BMI≥30 and trouble accessing healthcare services) were common to both the hospitalised and non-hospitalised groups. There is some evidence to suggest that among the hospitalised group, Māori have higher risk of disability relative to non-Māori. Conclusions At 24 months considerable disability is borne, equally, by hospitalised and non-hospitalised groups. However, predictors of disability are not necessarily consistent between the hospitalised and non-hospitalised groups, suggesting caution in generalising results from one group to the other.

Difficulties in functioning 1 year after injury: the role of preinjury sociodemographic and health characteristics, health care and injury-related factors.

OBJECTIVE To identify the role of preinjury sociodemographic and health characteristics, injury and injury-related health care characteristics in determining functional outcomes 12 months after injury. DESIGN Prospective cohort study involving 1-year follow-up. SETTING Community. PARTICIPANTS Study participants (N=2282; age range, 18-64y inclusive) were those in the Prospective Outcomes of Injury Study who completed the 12-month interview. The original cohort of 2856 were injured and registered with New Zealands national no-fault injury insurance agency. With the exception of injury and hospitalization, information on predictors and outcomes was obtained directly from the participants, primarily by telephone interviews, approximately 3 and 12 months after their injury. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES The functional outcomes of interest were the 5 dimensions of the EQ-5D plus a cognitive dimension. Our multivariate analyses included adjustment for preinjury EQ-5D status and time between injury and the 12-month interview. RESULTS Substantial portions of participants continued to have adverse outcomes, especially pain/discomfort, 12 months after their injury. The significance of factors varied by outcome. Factors adversely associated with at least 3 of the 6 outcomes were preinjury EQ-5D status, being female, aged 45 to 64 years, inadequate household income, preinjury disability, 2 or more prior chronic illnesses, smoking regularly, dislocation or sprains to the spine or upper extremities, and having a relatively severe injury. CONCLUSIONS A range of preinjury sociodemographic and health characteristics are associated with several adverse functional outcomes 1 year after injury, independent of the nature and severity of injury. The latter, however, also have independent effects on the outcomes.

The relationship between fatigue-related factors and work-related injuries in the saskatchewan farm injury Cohort Study†

BACKGROUND The objective was to examine the relationship between seasonal variations in sleep quantity and work-related injuries on Saskatchewan farms. METHODS A cross-sectional analysis of data from the Saskatchewan Farm Injury Cohort Study was conducted. Analyses were restricted to workers, aged ≥16 years. The primary outcome was work-related injury in the last year. Logistic regression models were used to identify associations between sleep quantity and farm injury. RESULTS After controlling for confounding variables peak production season sleep was not associated with increased odds of injury. However, those obtaining ≤5 hr sleep per night during non-peak production seasons had increased odds of injury (OR 2.42, 95% CI 1.04-5.59) compared with those sleeping ≥7 hr per night. CONCLUSIONS We identified that restricted sleep durations, in certain seasons, placed farmers, and farm workers at risk of injury. Agricultural injury intervention programs need to consider the role of seasonal-related variations in sleep on farm injury.

Factors associated with non-participation in one or two follow-up phases in a cohort study of injured adults

Objective To identify factors associated with non-participation at the 12-month and 24-month follow-up phases of a prospective cohort study of injury outcomes. Methods Associations between non-participation at follow-up phases and a range of sociodemographic, injury, health, outcome and administrative factors were examined. Results An individuals non-participation at 12 months did not necessarily mean non-participation at 24 months. Sociodemographic factors were the most salient for non-participation, regardless of the number of follow-up phases or specific phase considered. Conclusions Retention rates in prospective cohort studies of injury outcome may be improved by follow-up of everyone irrespective of previous non-participation, focusing resources to retain men, young adults, indigenous people and those living with people other than family members, and by ensuring that multiple alternative participant contacts are obtained. There is sufficient evidence to be concerned about potential bias given that several of the factors we, and others, have identified as associated with non-participation are also associated with various functional and disability outcomes following injury. This suggests detailed investigations are warranted into the effect non-participation may be having on the estimates for various outcomes.

Do outcomes differ between work and non-work-related injury in a universal injury compensation system? Findings from the New Zealand Prospective Outcomes of Injury Study

BackgroundPoorer recovery outcomes for workers injured in a work setting, as opposed to a non-work setting, are commonly attributed to differences in financial gain via entitlement to compensation by injury setting (ie. workers compensation schemes). To date, this attribution hasn’t been tested in a situation where both work and non-work-related injuries have an equivalent entitlement to compensation. This study tests the hypothesis that there will be no differences in recovery outcomes for workers by injury setting (work and non-work) within a single universal entitlement injury compensation scheme.MethodsWorkforce active participants from the Prospective Outcomes of Injury Study (POIS) cohort were followed up at 3- and 12-months following injury. Participants who were injured in the period June 2007- May 2009 were recruited from New Zealand’s universal entitlement injury compensation scheme managed by the Accident Compensation Corporation (ACC). An analysis of ten vocational, disability, functional and psychological recovery outcomes was undertaken by injury setting. Modified Poisson regression analyses were undertaken to examine the relationship between injury setting and recovery outcomes.ResultsOf 2092 eligible participants, 741 (35%) had sustained an injury in a work setting. At 3 months, workers with work-related injuries had an elevated risk of work absence however, this difference disappeared after controlling for confounding variables (adjusted RR 1.10, 95% CI 0.94-1.29). By 12 months, workers with work-related injuries had poorer recovery outcomes with a higher risk of absence from work (aRR 1.37, 95% CI 1.10-1.70), mobility-related functional problems (aRR 1.35, 95% CI 1.14-1.60), disability (aRR 1.32, 95% CI 1.04-1.68) and impaired functioning related to anxiety/depression (aRR 1.21, 95% CI 1.00-1.46).ConclusionOur study, comparing recovery outcomes for workers by injury setting within a single universal entitlement injury compensation scheme, found mixed support for the hypothesis tested. After adjustment for possible covariates recovery outcomes did not differ by injury setting at 3 months following injury, however, by 12 months vocational, disability and some functional outcomes, were poorer for workers with work-related injuries. Given our findings, and other potential mechanisms for poorer outcomes for workers with work-related injuries, further research beyond differences in entitlement to compensation should be undertaken to inform future interventions.

Ascertainment of occupational histories in the working population: The occupational history calendar approach

BACKGROUND self-reported occupational histories are an important means for collecting historical data in epidemiological studies. An occupational history calendar (OHC) has been developed for use alongside a national occupational hazard surveillance tool. This study presents the systematic development of the OHC and compares work histories collected via this calendar to those collected via a traditional questionnaire. METHODS the paper describes the systematic development of an OHC for use in the general working population. A comparison of data quality and recall was undertaken in 51 participants where both tools were administered. RESULTS the OHC enhanced job recall compared with the traditional questionnaire. Good agreement in the data captured by both tools was observed, with the exception of hazard exposures. CONCLUSIONS a calendar approach is suitable for collecting occupational histories from the general working population. Despite enhancing job recall the OHC approach has some shortcomings outweighing this advantage in large-scale population surveillance.