Hospitalization for Suicide Ideation or Attempt: 2008–2015

We used the Pediatric Health Information System (PHIS) database (Children’s Hospital Association, Lenexa, KS), which contains clinical and billing data from 49 children’s hospitals in the United States, to identify ED encounters, observation stays, and inpatient hospitalizations for children and adolescents 5 to 17 years of age between 2008 and 2015 using current procedural terminology codes. Member hospitals represent 17 of the 20 major metropolitan areas across the United States. Hospitals with incomplete PHIS data during the study period were excluded. Encounters with ≥1 primary or secondary discharge diagnosis codes (International Classification of Diseases, Ninth Revision) were classified as SI by using the V62.84 code (suicidal ideation). Encounters were classified as SA by using an algorithm previously validated in children and adolescents that used external cause-of-injury codes (E-codes 950–959) and International Classification of Diseases, Ninth Revision, Clinical Modification codes corresponding to potential mechanisms or injuries resulting from suicidal behavior (Supplemental Table 2).²⁵ This algorithm, derived from administrative claims data, produced a high positive predictive value (85%) for suicidal behavior, particularly with episodes resulting in hospitalization. Complex chronic conditions (CCCs) were also identified by using a separate previously validated algorithm to examine any trends among children and adolescents with CCCs, specifically patients classified as having technology dependence or organ transplant.²⁶ 

The outcome was the percentage of total encounters for SI and SA in each month of the study period. This was calculated by dividing the number of SI and SA encounters by the total number of encounters in each month.

We summarized characteristics of the population using frequencies and percentages for categorical variables and median and interquartile ranges (IQRs) for continuous variables. We examined monthly trends in SI and SA encounters across the study period using an autoregressive integrated moving average linear regression model to account for first order autocorrelation in the error terms of consecutive observations and clustered on hospital. This model also included a term for calendar month to account for postulated seasonal fluctuations in encounters for SI and SA. Using this model, we calculated the average annual change in the percentage of SI and SA encounters over the study period, and we compared the absolute difference in the percentage of SI and SA encounters between 2015 and 2008. We created secondary models for subgroups defined by age (5–11, 12–14, and 15–17 years), sex, and race and/or ethnicity. Age subgroups were based on commonly accepted definitions for late childhood, early, and late adolescence.²⁷ 

To examine seasonal trends in SI and SA encounters, we calculated the mean percentage of annual SI and SA encounters in each calendar month and seasonal quarter. Finally, we calculated the mean absolute difference in the percentage of annual SI and SA cases in each quarter from the quarter with the lowest mean percentage of annual SI and SA cases as the reference (summer). All analyses were performed by using SAS version 9.4 (SAS Institute, Inc, Cary, NC), and a P < .05 was considered statistically significant. This study was approved by the Institutional Review Board at Vanderbilt University Medical Center.

During the study period, we identified 115 856 encounters for SI and SA, representing 1.21% of the 9 574 229 total encounters across 31 hospitals (Table 1). More than half of SI and SA encounters resulted in an inpatient hospitalization in a children’s hospital (n = 67 588; 58.3%); of these, 8913 (13.2%) required intensive care. Half of encounters were adolescents 15 to 17 years old (n = 58 160; 50.2%), 42 844 were 12 to 14 years (37%), and 14 852 were 5 to 11 years (12.8%). Girls composed nearly two-thirds of encounters (n = 74 599; 64.4%).

SI and SA encounters, expressed as a percentage of total annual encounters per year, more than doubled over the study period, increasing from 0.66% in 2008 to 1.82% in 2015 (absolute difference in percent: 1.16; 95% confidence interval [CI]: 1.13 to 1.18; P < .001). This represented an average annual increase of 0.16 percentage points (95% CI 0.15 to 0.17; P < .001) (Fig 1). Over this period, total annual encounters for all diagnoses increased from 963 919 to 1 376 498 encounters (an increase of 43%), and total annual encounters for SI and SA increased from 6392 to 25 085 encounters (an increase of 292%); increases were seen in both ED and inpatient settings, with slightly higher increases noted in ED encounters, compared with inpatient encounters (Supplemental Table 3).

Significant increases were noted across all 3 age groups (Fig 2, Supplemental Table 4) but were lower for 5- to 11-year-olds (average annual increase 0.02 percentage points [95% CI 0.01 to 0.02]) compared with 12- to 14-year-olds (average annual increase 0.25 percentage points [95% CI 0.21 to 0.27]) and 15- to 17-year-olds (average annual increase 0.27 percentage points [95% CI 0.23 to 0.30]) (P < .001 for both comparisons). Significant increases were seen in both girls (average annual increase 0.14 percentage points [95% CI 0.13 to 0.15]) and boys (average annual increase 0.10 percentage points [95% CI 0.09 to 0.11]), but were higher for girls (P < .001) (Fig 3, Supplemental Table 5).

Regarding race and ethnicity, increases in SI and SA encounters were seen across all age groups. Increases as a total percentage of all SI and SA encounters were highest in non-Hispanic white youth (average annual increase 0.18 percentage points [95% CI 0.16 to 0.20], followed by youth of other races (average annual increase 0.09 percentage points [95% CI 0.07 to 0.11]), non-Hispanic African American youth (average annual increase 0.09 percentage points [95% CI 0.08 to 0.10]), and Hispanic youth (average annual increase 0.05 percentage points [95% CI 0.04 to 0.06]) (Fig 4, Supplemental Table 6). When we examined trends in socioeconomic status (defined as median household income by quartiles), the lowest quartile (1) was the only subgroup to reveal a slight decrease over the study period (26.3% in 2008, compared with 23.1% in 2015). All other subgroups (quartile 2, quartile 3, and quartile 4) revealed slight increases, with the largest increase seen in quartile 3 (Table 1). We also examined geographic trends over the study period using the patients’ zip code. Although median distance traveled for encounter increased slightly over this period, the percentage of children traveling ˃20 miles for each encounter did not significantly increase over time (Table 1). Regarding patient type, inpatient encounters composed the majority of encounters (58.3%) compared with ED encounters (41.7%). Length of stay was examined by subgroup. Over half of all encounters fell into the 0- to 1-day subgroup, although a substantial proportion (15.8%) composed the ˃7-days group, requiring prolonged hospitalization. A total of 7.7% of patients were admitted to ICU, with only a slight decrease noted over the period studied.

We observed seasonal variation in encounters for SI and SA (Fig 5). The lowest frequency of encounters occurred during summer months. On average, during the 8 years included in the study, only 18.5% (95% CI 18.0 to 19.0) of total annual SI and SA encounters occurred during summer months. July only accounted for 5.9% of all SI and SA encounters (95% CI 5.6 to 6.1). Peaks were highest in fall and spring. October accounted for nearly twice as many encounters as reported in July (9.9% [95% CI 9.2 to 10.7]), followed by March (9.7% [CI 9.2 to 10.1]) (Fig 4, Supplemental Table 7).

Encounters for SI and SA encounters more than doubled between 2008 and 2015. More than half of these resulted in hospitalization. The observed increases appear to be consistent with reports of increasing prevalence of depression and mood disorders in US children and adolescents.²⁸ Suicide deaths among 10- to 14-year-olds significantly increased from 2006 to 2014, a time period similar to the one we examined; according to data from the Centers for Disease Control and Prevention, suicide is now as common a cause of death as motor vehicle accidents in this age.^29,30 

Previous SAs have been shown to be a significant predictor of future attempts in children and adolescents. We did not specifically examine suicide deaths or differentiate between SI and SA encounters, but increases in SI and SA encounters were seen across all age groups. Greatest increases in SI and SA encounters were seen among 12- to 14-year-olds and 15- to 17-year-olds but were also noted among 5- to 11-year-olds. Although suicide in elementary school children is rare, the authors of 2 recent studies of children aged 5 to 11 years have suggested these rates may be increasing, particularly among African American boys.^31,32 

Previously reported data has revealed that adolescent girls appear to be at increasing risk for SI, SA, and mood disorders. Larger increases in depressive symptoms in 12- to 17-year-old girls, compared with boys, have also been reported from 2005 to 2014.²⁸ We noted a similar increase in the percent of SI and SA encounters in girls, compared with boys. These findings have important implications for exploring age- and sex-specific approaches to suicide screening and prevention interventions, as well as further research in examining causal factors for SI and SA.

Most studies still reveal an overall higher risk for suicidal behavior among white youth than any other group,³³ similar to the findings in our study. We did not see dramatic shifts among race and ethnicity over the study period, but we did not specifically examine race by age or sex subgroups and acknowledge we only studied individuals who sought care for SI and/or SA; cultural and economic barriers to seeking mental health care remain important considerations. Average distance traveled and the percentage of children traveling ˃20 miles for care did increase slightly over this study period, but we did not examine specific geographic trends more closely. Although children’s hospitals included in the PHIS database often serve a large geographic area, general hospitals have historically carried a larger burden of pediatric hospitalizations for mental health disorders compared with those in the PHIS database,¹⁹ and we are unable to make any conclusions regarding geographic trends over the study period.

Several reasons have been suggested for the growing increase in depression, SI and SA, and suicide among children and adolescents. Bullying^34,35 (particularly the rise of social media and cyberbullying^36,37), the decreasing age of puberty in girls,^38,39 and trends in the use of antidepressants⁴⁰ have been proposed as possible factors. The effect of the economic crisis of 2008 has also been examined, although its effect on adolescent suicide-related behavior remains less understood than adult behavior.^41,–43 We did not observe any significant trends between quartiles of median household income or changes in payer mix over the study period.

Most striking was the marked seasonal variation in percentage of total SI and SA encounters we observed throughout the study period. July had the lowest mean percentage of annual cases (5.9%), followed by June and August. Summer months accounted for a mean 18.5% of annual cases; percentages nearly doubled in spring and fall months. Assuming that the majority of SI and SA encounters represented children who were enrolled in traditional academic calendars, rates of SI and SA encounters were higher during the academic year, compared with summer months. To our knowledge, only one other previous study in the medical literature has reported a correlation between risk of SI and SA among children and adolescents and the academic school year.⁴⁴ Lueck et al⁴⁴ found an incidence rate ratio of 2.18 for ED visits related to psychiatric complaints (including SI, SA, homicidal ideation, and involuntary psychiatric holds) during school attendance compared with school vacation times. Hansen and Lang⁴⁵ reviewed mortality data from 1980 to 2004 and concluded that youth suicides were least likely to occur in months when students were on summer vacation, whereas adult suicide is most likely to occur during those same months,^46,47 suggesting that youth may face increased stress and decreased mental health when school is in session. Recent media attention has been focused on how schools and social media impact behavior and the role social contagion may play.^48,49 With our findings, we underscore the need for future work to explore the relationship between school and suicidal ideation, recognizing that the role of academics is a complex one, and there may also be other additional influences at play regarding seasonality.^50,51 

One question raised by our study is whether the overall increase and seasonal variation in SI and SA encounters represent true differences in increasing incidence of SI and SA or reflect improved recognition and screening. The use of both outpatient and inpatient specialty mental health care services increased during the time period we studied.^50,51 Reported in data from the National Surveys on Drug Use and Health was an increase in 12-month prevalence of major depressive episodes, a strong predictor for SI and SA, among 12- to 17-year-olds from 2005 to 2014.²⁸ In addition, suicide incidence rates increased for all age groups over this period, including 10- to 17-year-olds.²⁹ Thus, it seems plausible that the increase in SI and SA encounters are more reflective of general trends reported in the community prevalence of SI and SA, although other factors, such as declining availability (and increased use) of inpatient psychiatric beds may have also contributed. Much emphasis has been placed on improved screening for youth depression and SI in primary care,^52,53 recognizing the crucial role primary care providers play in providing appropriate evaluation and treatment. However, less than half of young people with a mental disorder seek treatment,⁵⁴ and current literature suggests only a minority of individuals affected with depression receive care.^55,56 Only a minority of pediatricians report that they feel comfortable treating depression.^22,–24 If pediatricians are screening patients for depression and SI more often but are not equipped to manage these conditions, they may be more likely to refer these patients to higher levels of care, including children’s hospitals, to access mental health care.

Several limitations of our study warrant consideration. It is possible that some nonsuicidal self-harm encounters were misclassified as SI and/or SA. Nonsuicidal self-harm appears to be increasing among adolescents.^57,58 The algorithm we used to identify SI and SA encounters previously revealed a high positive predictive value (82.6%), but we acknowledge it was derived from youth enrolled in Medicaid from a single state; thus, it may not be generalizable to youth in other states to those with other insurance coverage. Although individuals with nonsuicidal self-harm are less likely to present for emergency care or hospitalization,⁵⁹ we acknowledge considerable overlap exists between these 2 populations.^60,61 Nevertheless, increases in either group raises cause for concern. The rate of increase in the identification of SI using the V62.84 code is similar to rates of increase reported in other studies in which authors examine other data sources. Although this code was introduced in 2006 and initially resulted in a marked increase in recorded suicidal ideation among ED visits,⁶² we chose to begin our study period in 2008 to minimize measurement artifacts related to time lag in implementation of new International Classification of Diseases, Ninth Revision codes. For similar reasons, we chose to end our study period in 2015 when new International Classification of Diseases, 10th Revision codes for SI were introduced and included corresponding International Classification of Diseases, 10th Revision codes for October through December of 2015.

The PHIS database is limited to freestanding children’s hospitals; thus, our findings are only applicable to these hospitals. Authors of future studies that include data from community hospitals could help corroborate whether similar trends have occurred in community hospital settings. The ecological design of our study precluded assessment of biological or psychosocial factors contributing to SI and SA. In addition, we did not differentiate encounters between SI and SA, and we were also unable to determine whether the increasing trends observed reflected increases in incident SI and SA, recurrent SI and SA, or both. We did not examine completed suicides or readmissions for SI and SA, which are important correlates for SI and SA. Finally, we were unable to examine referral sources for children and adolescents directed to children’s hospitals for evaluation or disposition at discharge.

Our findings that ED and inpatient children’s hospital encounters for SI or SA have increased over the past decade underscore the increasing impact of mental health disorders in youth on children’s hospital services and the increasing role they appear to play in managing and treating youth with SI or SA. We hope our study can be used to inform future effective strategies for managing the growing burden of children with behavioral health issues. Children’s hospitals are unique in that many sites serve as primary training locations for a variety of pediatric health and behavioral health care providers. They are well positioned to help explore future interventions and research in quality improvement as well as to advocate for access to pediatric mental health care. In addition, the finding that SI and SA encounters occur more often during the academic school year underscores the need for further research in the role that schools may play as well as inform hospital capacity planning and workflow. Recognition of this increasing burden on children’s hospitals is paramount in helping to inform future strategies for suicide prevention and treatment and to ensure that interventions to reverse this concerning trend continue to reach the individuals at highest risk.

CCC

complex chronic condition

CI

confidence interval

ED

emergency department

IQR

interquartile range

PHIS

Pediatric Health Information System

SA

suicide attempt

SI

suicide ideation