A retrospective cohort study comparing non-fatal self-harm emergency department visits between Canadian veterans living in Ontario and matched civilians

Mental health service use among Canadian veterans within the first 5 years following service: methodological considerations for comparisons with the general population

INTRODUCTION

Previous research comparing veteran and civilian mental health (MH) outcomes often assumes stable rates of MH service use over time and relies on standardisation or restriction to adjust for differences in baseline characteristics. We aimed to explore the stability of MH service use in the first 5 years following release from the Canadian Armed Forces and the Royal Canadian Mounted Police, and to demonstrate the impact of using increasingly stringent matching criteria on effect estimates when comparing veterans with civilians, using incident outpatient MH encounters as an example.

METHODS

We used administrative healthcare data from veterans and civilians residing in Ontario, Canada to create three hard-matched civilian cohorts: (1) age and sex; (2) age, sex and region of residence; and (3) age, sex, region of residence and median neighbourhood income quintile, while excluding civilians with a history of long-term care or rehabilitation stay or receipt of disability/income support payments. Extended Cox models were used to estimate time-dependent HRs.

RESULTS

Across all cohorts, time-dependent analyses suggested that veterans had a significantly higher hazard of an outpatient MH encounter within the first 3 years of follow-up than civilians, but differences were attenuated in years 4-5. More stringent matching decreased baseline differences in unmatched variables and shifted the effect estimates, while sex-stratified analyses revealed stronger effects among women compared with men.

CONCLUSIONS

This methods-focused study demonstrates the implications of several study design decisions that should be considered when conducting comparative veteran and civilian health research.

The impact of a cancer diagnosis on nonfatal self-injury: a matched cohort study in Ontario

BACKGROUND

Psychological distress following a cancer diagnosis potentially increases the risk of intentional, nonfatal self-injury. The purpose of this work is to evaluate and compare rates of nonfatal self-injury among individuals in Ontario diagnosed with cancer against matched controls with no history of cancer.

METHODS

Adults in Ontario diagnosed with cancer from 2007 to 2019 were matched to 2 controls with no history of cancer, based on age and sex. We calculated the absolute and relative difference in rates of nonfatal self-injury in the 5 years before and after the index date (date of cancer diagnosis and dummy date for controls). We used crude difference-in-differences methods and adjusted Poisson regression-based analyses to examine whether the change in rates of nonfatal self-injury before and after index differed between cancer patients and controls.

RESULTS

The cohort included 803 740 people with cancer and 1 607 480 matched controls. In the first year after diagnosis, individuals with cancer had a 1.17-fold increase in rates of nonfatal self-injury (95% confidence interval [CI] 1.03-1.33) compared with matched controls, after accounting for pre-existing differences in rates of nonfatal self-injury and other clinical characteristics between the groups. Rates of nonfatal self-injury remained elevated in the cancer group by 1.07-fold for up to 5 years after diagnosis (95% CI 0.95-1.21).

INTERPRETATION

In this study, incidence of nonfatal self-injury was higher among individuals diagnosed with cancer, with the greatest impact observed in the first year after diagnosis. This work highlights the need for robust and accessible psychosocial oncology programs to support mental health along the cancer journey.

Association of Patient-Reported Outcomes With Subsequent Nonfatal Self-injury After a New Cancer Diagnosis

Importance

Nonfatal self-injury (NFSI) is a patient-centered manifestation of severe distress occurring in 3 out of 1000 patients after cancer diagnosis. How to identify patients at risk for NFSI remains unknown.

Objective

To examine the associations between patient-reported outcome measures and subsequent NFSI in patients with cancer.

Design, Setting, and Participants

This population-based matched case-control study included adults with a new cancer diagnosis reporting an Edmonton Symptom Assessment System (ESAS) score within 36 months of diagnosis in Ontario, Canada, 2007 to 2019. Data analysis was performed January 2007 to December 2019.

Main Outcomes and Measures

Cases included patients with NFSI, and controls were patients without NFSI. Cases and controls were matched 1:4. Multivariable conditional logistic regression assessed the association between moderate to severe ESAS symptom scores and total ESAS (t-ESAS, range 0-90) score with NFSI in the subsequent 180 days.

Results

Of 408 858 patients reporting 1 or more ESAS assessments, 425 patients experienced NFSI and reported an ESAS score in the preceding 180 days. Of those, 406 cases were matched to 1624 control patients without an NFSI. Cases reported a higher proportion of moderate to severe symptoms and higher t-ESAS score than controls prior to the event. After adjustment, moderate to severe anxiety (odds ratio [OR], 1.61; 95% CI, 1.14-2.27), depression (OR, 1.66; 95% CI, 1.20-2.31), and shortness of breath (OR, 1.65; 95% CI, 1.18-2.31) and each 10-point increase in t-ESAS score (OR, 1.51; 95% CI, 1.40-1.63) were independently associated with higher odds of subsequent NFSI.

Conclusions and Relevance

In this case-control study, reporting moderate to severe anxiety, depression, and shortness of breath and an increasing t-ESAS score after cancer diagnosis were associated with higher odds of NFSI in the following 180 days. These data support the prospective use of routine ESAS screening as a means of identifying patients at higher risk for NFSI to improve supportive care.

Incidence of and Factors Associated With Nonfatal Self-injury After a Cancer Diagnosis in Ontario, Canada

IMPORTANCE

Psychological distress is a key component of patient-centered cancer care. While a greater risk of suicide among patients with cancer has been reported, more frequent consequences of distress, including nonfatal self-injury (NFSI), remain unknown.

OBJECTIVE

To examine the risk of NFSI after a cancer diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study used linked administrative databases to identify adults diagnosed with cancer between 2007 and 2019 in Ontario, Canada.

EXPOSURES

Demographic and clinical factors.

MAIN OUTCOMES AND MEASURES

Cumulative incidence of NFSI, defined as emergency department presentation of self-injury, was computed, accounting for the competing risk of death from all causes. Factors associated with NFSI were assessed using multivariable Fine and Gray models.

RESULTS

In total, 806 910 patients met inclusion criteria. The mean (SD) age was 65.7 (14.3) years, and 405 161 patients (50.2%) were men. Overall, 2482 (0.3%) had NFSI and 182 (<0.1%) died by suicide. The 5-year cumulative incidence of NFSI was 0.27% (95% CI, 0.25%-0.28%). After adjusting for key confounders, prior severe psychiatric illness, whether requiring inpatient care (subdistribution hazard ratio [sHR], 12.6; 95% CI, 10.5-15.2) or outpatient care (sHR, 7.5; 95% CI, 6.5-8.8), and prior self-injury (sHR, 6.6; 95% CI, 5.5-8.0) were associated with increased risk of NFSI. Young adults (age 18-39 years) had the highest NFSI rates relative to individuals aged 70 years or older (sHR, 5.4; 95% CI, 4.5-6.5). The magnitude of association between prior inpatient psychiatric illness and NFSI was greatest for young adults (sHR, 17.6; 95% CI, 12.0-25.8). Certain cancer subsites were also associated with increased risk, including head and neck cancer (sHR, 1.5; 95% CI, 1.2-1.9).

CONCLUSIONS AND RELEVANCE

In this study, patients with cancer had a higher incidence of NFSI than suicide after diagnosis. Younger age, history of severe psychiatric illness, and prior self-injury were independently associated with risk of NFSI. These exposures appeared to act synergistically, placing young adults with a prior mental health history at the greatest risk of NFSI. These factors should be used to identify at-risk patients.