Response to a Single Question May Flag Suicide Risk

Deborah Brauser

December 06, 2013

A specific response to a single question from a commonly used depression scale may help clinicians flag patients at increased risk for suicide, new research suggests.

A study of more than 84,000 patients with depressive symptoms who completed the Patient Health Questionnaire (PHQ-9) at every outpatient visit for depression care during a 4-year period showed that respondents who reported that they thought about death or self-harm "nearly every day" had more than a 6-fold increased risk for suicide attempt compared with respondents who did not consider these options.

According to investigators, led by Gregory E. Simon, MD, MPH, from the Group Health Research Institute in Seattle, Washington, patients who reported thoughts of death or self-harm "more than half the days" or "nearly every day" accounted for 53% of suicide attempts and 54% of suicide deaths.

Interestingly, the immediate risk for suicidal behavior after completing the PHQ-9 was low, but the risk increased during several days and continued to grow for several months after.

"Suicidal ideation should be viewed as an enduring vulnerability rather than simply a short-term crisis," write the investigators. "These findings emphasize the need for sustained and organized follow-up care to address ongoing risk."

The study was published in the December issue of Psychiatric Services.

A Leading Cause of Death

According to the investigators, in 2010 there were 38,000 suicide deaths in the United States, making suicide the 10th leading cause of death.

In addition, suicide attempts have led to approximately 200,000 annual hospitalizations and 600,000 visits to emergency departments (EDs).

"Early intervention to reduce this morbidity and mortality would require both accurate screening tests and effective interventions for persons found to be at risk," write the researchers.

They add that, before their study, no evidence had shown that a screening could accurately identify this at-risk population.

"Consequently, the US Preventive Services Task Force and others do not recommend screening for risk of suicidal behavior," the investigators report.

"Nevertheless, increasing use of standard depression outcome questionnaires means that clinicians treating depression will frequently encounter patients who report thoughts of death or self- harm."

For the study, investigators evaluated electronic health record data from 84,418 individuals who were part of the Group Health Cooperative, a large, integrated healthcare system serving the states of Washington and Idaho.

All participants were older than 12 years; they completed 207,265 PHQ-9s from January 2007 to January 2011 as part of outpatient treatment for depression during visits to primary care or mental health speciality providers.

Patient data were then linked to insurance claims and death certificates reporting suicide attempts or suicide deaths.

Suicide Deaths, Attempts

Item 9 on the PHQ-9 specifically asks, "Over the last 2 weeks, how often have you been bothered by thoughts that you would be better off dead, or of hurting yourself in some way?" Answer options were "not at all," "several days," "more than half the days," or "nearly every day."

Results showed that there were 46 suicide deaths and 709 nonfatal suicide attempts among all of the participants. Of the suicide attempts, 371 led to hospitalization and 338 led to ED or outpatient treatment.

Of the total group assessed, 77% answered "not at all" to item 9 on the PHQ-9, 14% answered "several days," 5% answered "more than half the days," and 4% answered "nearly every day."

Those responding "nearly every day" had a relative hazard ratio (HR) of 6.37 for suicide attempt (95% confidence interval [CI], 5.07 - 8.01) compared with those who responded "not at all." Those who responded with "more than half the days" had a relative HR of 4.12 (95% CI, 3.34 - 5.08).

Further analysis showed a significant "linear relationship between item 9 score and risk of subsequent suicide attempt, with a 91% increase in risk…for each one-step increase in reported frequency of thoughts of death or self-harm" (HR, 1.91; 95% CI, 1.79 - 2.04; P < .001), report the investigators.

The relative HR for suicide death in participants who responded with "nearly every day" to item 9 was 5.28 (95% CI, 2.14 - 13.03) compared with those who responded "not at all"; it was 5.89 (95% CI, 3.14 - 11.08) for those who responded with "more than half the days."

"Wide confidence limits for HRs reflect the small numbers of suicide deaths," explain the researchers.

There was also a significant (P < .001) linear relationship between subsequent suicide death and item 9 score, with an HR of 1.92 (95% CI, 1.53 - 2.41) for each increased step in suicidal thought frequency.

Practical Guidance for Everyday Practice

The investigators note that because the PHQ-9 was designed to measure depression severity and not suicidal behavior specifically, the wording of item 9 could lead to the false inclusion or exclusion of certain patients. Instead, using a measurement that was specifically created for suicidal ideation could be potentially more accurate in predicting these risks.

"This report, however, intends to provide practical guidance regarding a measure that is widely and increasingly used in everyday practice."

They add that although the results do not justify population-based screening, it is important to note that in a measurement that is already commonly used, 1 in 10 of the participants reported thoughts of death or self-harm at least half of their days.

"And those patients experienced a markedly increased risk of subsequent suicide attempt and suicide death. For this high-risk group, additional assessment is clearly indicated," write the researchers.

The study was funded by the National Institute of Mental Health. The study authors have disclosed no relevant financial relationships.

Psychiatr Serv. 2013;64:1195-1202. Abstract

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