Research paper
Suicidal ideation reported on the PHQ9 and risk of suicidal behavior across age groups

https://doi.org/10.1016/j.jad.2017.03.037Get rights and content

Highlights

  • The Joint Commission recommends all patients be screened for suicide.

  • Nearly daily suicidal ideation on PHQ9 predicted risk of suicide attempts and deaths.

  • Suicidal ideation was a robust predictor of suicide attempts and deaths in all ages.

  • Risk of suicide attempts and deaths persisted over two years.

Abstract

Objective

The Joint Commission recommends all patients be screened for suicide. However, differences in suicide attempt and death rates may affect how well tools predict risk across age groups. Our objective was to determine whether item 9 of the Patient Health Questionnaire (PHQ9) predicts risk for suicide attempts and deaths across age groups.

Methods

PHQ9s completed by adult outpatients treated for mental health conditions in 2010–2012 at four Mental Health Research Network-affiliated healthcare systems were used to measure depression severity and suicidal ideation. Suicide attempts were identified via ICD-9 codes and suicide deaths via ICD-10 codes and state death certificates.

Results

In all, 939,268PHQ9s were completed by 297,290 outpatients. Compared to those without, those with nearly daily suicidal ideation were 5-to-8 times more likely to attempt suicide and 3-to-11times more likely to die by suicide within 30 days, and 2-to-4times more likely to attempt suicide and 2-to-6 times more likely to die by suicide within 365 days. The increased risk of suicide death for those with any level of suicidal ideation persisted over two years. The relationships between suicide thoughts and attempts and deaths were similar across age groups.

Limitations

Our sample was limited to outpatients completing a PHQ9 and relied on pre-existing clinical and administrative data.

Conclusions

Suicidal ideation reported on the PHQ9 was a robust predictor of suicide attempts and deaths regardless of age, and this increased risk persisted for two years. Healthcare systems should address both the immediate and sustained risk for suicide for patients of all ages.

Introduction

Suicide is a major public health concern, with rates of suicide in the United States now surging to levels not seen in nearly 30 years (CDC Increase in Suicide in the United States, 2016). An estimated 3.9% of adults in the U.S. (9.3 million people) have had suicidal thoughts in the past year (Suicide: Facts at a glance, 2015). Rates of suicidal ideation are highest among young adults (aged 18–25) at 7.4%, and lowest in older adults (aged 50 or older) at 2.7%. Approximately 1.1% of U.S. adults (2.7 million people) made a plan for attempting suicide in the past year, highest in young adults at 2.5% and lowest among older adults at 0.6%. About 0.6% of U.S. adults (1.3 million people) attempted suicide in the past year, with the majority of these adults (85%, or 1.1 million people) having made a plan for attempting suicide. A total of 41,149 adults died by suicide in the U.S. in 2013, making suicide the tenth leading cause of death (Suicide: Facts at a glance, 2015).

Results for lifetime prevalence of suicidal ideation and attempts globally have been similar. In a study of 84,850 adults interviewed across 17 countries, 9.2% reported lifetime suicidal ideation, while 3.1% reported lifetime suicide plans and 2.7% reported at least one suicide attempt (Nock et al., 2008). Of note, 60% of people who developed suicidal ideation developed a plan for suicide in the first year after the onset of suicidal ideation. For those with suicidal ideation, 33.6% made a plan for suicide, while 29.0% made a suicide attempt. Over half (56.0%) of patients who had both suicidal ideation and a plan for suicide attempted suicide, compared to 15.4% of patients who had suicidal ideation without a plan.

Clearly, suicidal ideation increases risk for suicide, and having a plan for suicide greatly further increases this risk. However, to date, the U.S. Preventative Services Task Force has found insufficient evidence to adequately assess the risks or benefits of screening for suicide risk in primary care (LeFevre and Force, 2014). Since that 2014 recommendation, we reported that the Patient Health Questionnaire (PHQ9) can accurately identify primary care and mental health outpatients at increased risk of suicide attempts and deaths (Simon et al., 2016a). Patients who reported frequent thoughts of death or self-harm on the ninth question of the PHQ9 were 6 times more likely to attempt suicide and five times more likely to die by suicide in the following year than those who did not report such thoughts. Many healthcare systems essentially routinely screen for suicidal ideation as part of the widely administered PHQ9, and last year, the Joint Commission issued a Sentinel Event Alert recommending that healthcare systems screen all patients in all healthcare settings for suicide risk using a brief, standardized, evidence-based screening tool, such as the PHQ9 (Sentinel Event Alert 56, 2016).

The risk for suicide attempts and deaths is known to vary by age, with suicide death rates highest in people ages 45–64 (19.5 suicide deaths per 100,000) and 85 and older (19.3 per 100,000), relatively lower in those 30–44 (16.1 per 100,000) and 65–84 (16.2 per 100,000), and lowest in those 18–29 (13.9 per 100,000) (Injury Prevention, 2015). Suicide attempts also vary by age, with an estimated 25 suicide attempts for every death in younger adults but only 4 attempts per death in elderly adults (American Foundation for Suicide Prevention, 1, 2016). Overall, middle-aged adults account for the largest proportion of suicides (56%) (Web-based Injury Statistics Query and Reporting System WISQARS, 2016), and this group saw the largest increase – nearly 30% – in suicide deaths between 1999 and 2010 (Sullivan et al., 2013).

It is unclear whether these differences in rates of suicide attempts and deaths by age (Injury Prevention, 2015, American Foundation for Suicide Prevention, 1, 2016, Web-based Injury Statistics Query and Reporting System (WISQARS), 2016, Sullivan et al., 2013) might lead to differential risk prediction across age groups. Given this knowledge gap, along with the increasing use of the PHQ9 (Kroenke et al., 2001) and the Joint Commission's recommendation to screen all patients for suicide (Sentinel Event Alert 56 56, 2016), we conducted this study to determine if PHQ9 item 9 responses consistently predicted risk for suicide attempts and deaths across age groups in a large, diverse populations of outpatients across the U.S.

Section snippets

Data sources

The Mental Health Research Network (MHRN) is a consortium of public-domain research centers affiliated with 13 large not-for-profit integrated healthcare systems. Data included in this study were from four partner sites in the MHRN that were routinely administering PHQ9s to outpatients in 2010 through 2012: Group Health Cooperative, HealthPartners, Kaiser Permanente Colorado, and Kaiser Permanente Southern California. These healthcare systems provide comprehensive medical care, including mental

Results

Across four health systems, 297,290 outpatients completed 939,268 PHQ9s between January 1, 2010 and December 31, 2012 (Table 1). Of those PHQ9s, 70% were completed by women and 18–29, 30–44, 45–64, and 65+ year olds completed 17%, 27%, 40%, and 16% of PHQ9s, respectively. PHQ9s were most frequently completed by patients who self-identified as non-Hispanic white (74%;n=694,378) or Hispanic (10%; n=89,361), followed by patients who self-identified as Other or Mixed Race (6%; n=59,141),

Discussion

Suicidal ideation, as assessed by item 9 of the PHQ9, was a robust predictor of suicide attempts and deaths regardless of age in this very large and diverse sample of adult outpatients. The absolute risk of suicide attempt generally declined with age, while the absolute risk of suicide death generally increased with age. However, the relationships between suicidal ideation and suicide attempts and deaths were similar across all age groups. The risk of suicide attempts and deaths was highest in

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