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- MATERIALS AND METHODS
- AUTHOR CONTRIBUTIONS
Suicide is one of the highest public health priorities worldwide (1). The World Health Organization objectives for suicide prevention emphasize identification of high-risk groups (2). Suicidal ideation, referring to wishes that one's life would end or thoughts of harming or killing oneself, represents an important phase in the suicidal process and often precedes suicidal attempts or completed suicide (3, 4). Patients with chronic medical illnesses and especially those experiencing pain are more likely to report suicidal thoughts (5, 6). As a chronic condition frequently associated with pain, arthritis may increase the risk of suicidal ideation. Coping with the effects of arthritis on a daily basis can have detrimental consequences for the mental health of those affected.
Little is known about the occurrence of suicidal ideation among persons with arthritis (7, 8). One study showed that almost 11% of outpatients with rheumatoid arthritis (RA) experienced suicidal thoughts at the time of the study (7). However, the sample was small and was focused on RA, which represents only part of the arthritis population. Another study using a survey-based sample showed that suicidal ideation was approximately twice as common among adults with arthritis as those without (8). However, the association between arthritis and suicidal ideation in the general population, and whether arthritis differs from other chronic disorders in this association, remains poorly characterized. Most importantly, the subgroups of adults with arthritis at greatest risk for suicidal thoughts are not known. Suicidal ideation is the result of a complex set of interactions between predisposing factors, buffers, and more acute situational events. Focus on subgroups at high risk can help improve suicide prevention and intervention strategies in persons with arthritis.
To address these questions, we used data from the National Health and Nutrition Examination Survey (NHANES) for 2007–2008, the largest US survey that included questions about both suicidal thoughts and arthritis and related conditions such as pain. The purpose of this study was to determine the prevalence of suicidal ideation among adults with arthritis, and to identify subgroups of individuals with arthritis at greatest risk for suicidal thoughts. Additionally, to evaluate if the most important correlates among persons with arthritis differ from those of people with other chronic diseases, we compared results with those of people with diabetes mellitus and cancer.
Significance & Innovations
To our knowledge, this is the first population-based US study of suicidal ideation in adults with arthritis.
We identified subgroups of people with arthritis at highest risk for suicidal ideation.
The main correlate was depression, which was assessed by the Patient Health Questionnaire 8.
Similar risk factors were found in the diabetes mellitus and cancer groups.
- Top of page
- MATERIALS AND METHODS
- AUTHOR CONTRIBUTIONS
Suicidal ideation among adults with arthritis is of growing relevance to public health, given the increase in the projected prevalence of arthritis in US adults (23). Our study, using data from a nationally representative survey, showed that the prevalence of suicidal ideation in adults with arthritis was higher than that of persons without arthritis. Depression, anxiety, duration of arthritis, age, income:poverty ratio, social network, pain, alcohol use, excessive daytime sleepiness, and comorbidities were the most important correlates for suicidal thoughts among individuals with arthritis. Those with PHQ-8 scores between 18 and 24 and a short duration of arthritis (<4.5 years) were at highest risk for suicidal ideation.
Our findings were consistent with 2 previous studies showing that suicidal ideation was prevalent among adults with arthritis. One study examined 123 hospital outpatients with RA without including any control group, and the other used data from the Canadian Community Health Survey 2000–2001 (7, 8). A similar prevalence of suicidal thoughts among persons with arthritis, diabetes mellitus, and cancer was identified in our study, suggesting that the chronic nature of illness can impair the psychological well-being of people with these disorders (5, 6).
Despite continuing research, it remains difficult to predict which individuals are most vulnerable for suicidal behavior, which is never the consequence of a single cause (1). Mood disorders such as anxiety and particularly depression significantly increase the risk of suicidal thoughts in the general population and several medical conditions (24–26). Depression was also the main risk factor for suicidal ideation and suicide completion in studies of RA patients (7, 27). In our study, depression was the most important factor identifying subsets of individuals with arthritis affected with suicidal ideation. However, it is well established in the psychiatric literature that not only depression but also other mental illnesses (psychotic and personality disorders and alcohol/substance use), sociodemographic factors, and physical health problems contribute to suicidal ideation, each being interrelated (1, 28–30).
In our study, the risk for suicidal ideation was higher among adults ages 40–54 years compared to older people, those with a limited number of close friends or relatives, and those with a low income:poverty ratio (29, 31). Although suicide rates in elderly people have fallen in many countries, those in younger people have risen (1). Weak ties and low social support from friends or relatives have been significantly associated with suicidal thoughts in the literature (31, 32). Furthermore, data from psychiatric epidemiology surveys showed increased rates of suicidal ideation and suicidal attempts among adults with a low income and income:poverty ratio, which remained unchanged after adjusting for the presence of mental disorders (33, 34).
Regarding health behaviors and comorbidities, the results of our study were consistent with those of previous studies reporting that alcohol, smoking, and coexistence of arthritis with other chronic diseases were important correlates for suicidal thoughts (1, 35, 36). The screening for alcohol abuse is highly feasible in clinical practice and its detection should increase the suspicion for suicidal ideation in persons with depression. The presence of a general medical illness has been associated with an increased risk of both suicidal ideation and suicide attempts, and having more than one illness conferred a particularly high risk in the general population (37–39).
Persistent pain has been associated with elevated rates of suicidal behavior (40, 41). However, studies of chronic pain conditions have not adequately elucidated whether the increased risk of suicidal behavior is associated with pain per se or with the physical disability that pain produces (8, 42, 43). A recent review also suggested that sleep problems might be an indirect mechanism by which chronic pain is associated with suicidal thoughts (41). The present study indicates that mainly pain but also limitations in ADL and excessive daytime sleepiness were among the most important contributors for suicidal ideation in adults with arthritis, cancer, and diabetes mellitus. Excessive daytime sleepiness was a more important correlate than insomnia, possibly because it was much more prevalent than insomnia and therefore had a higher likelihood of demonstrating associations, but also because it may be a consequence of insomnia or a manifestation of depression.
Commonalities among the major correlates for suicidal ideation in individuals with arthritis, cancer, and diabetes mellitus include depression and anxiety, age, income:poverty ratio, social network, pain, binge drinking, and comorbidities. Eleven of the top 16 most important contributors for suicidal thoughts were common among arthritis and the other 2 chronic disease groups. This finding supports the general role of these factors in suicidal behavior among chronic diseases, regardless of the disease itself.
The results of the current study suggest that individuals with arthritis at high risk for suicidal thoughts should receive close monitoring and early intervention (44, 45). Self-report measures such as the PHQ-9 can be used as screening tools of depressive disturbances in outpatient clinics (44). Recognition and effective treatment of depression, anxiety, and comorbidities; enhancement of social support resources; and management of pain and physical disability are fundamentally important in reducing suicidal behavior (46–48). The strengths of this study include the large nationally representative sample and the wide range of sociodemographic, physical, and mental health factors examined. We also included pain and physical limitations, often present in persons with arthritis. We provided new information on the prevalence of suicidal ideation among individuals with arthritis, and on subgroups of people with arthritis most vulnerable for suicidal thoughts. The use of classification tree analysis helped to assess multiple correlates and their interactions to identify subgroups at greatest risk.
This study is limited in that the survey did not include some factors that may be associated with suicidal thoughts such as other psychiatric (e.g., personality disorders) or chronic pain diseases (abdominal pain, migraine). In addition, since the NHANES used a self-completed screening measure rather than an interview, we had to rely on the patient's interpretation of the question. However, the PHQ-9 is a screening instrument with high reliability and validity in the general population and various medical settings such as a primary care population, general hospital inpatients, and patients with rheumatic diseases (RA, osteoarthritis, fibromyalgia) (43, 49). Data on physician-diagnosed arthritis were also self-reported, but self-reports have been validated previously for surveillance purposes (10). Self-reported arthritis likely includes many types of arthritis that are represented in the study in proportion to their prevalence. An additional limitation is that our study cannot identify correlates of suicidal ideation that may be unique or specific to a given type of arthritis, and may not reflect correlates of suicidal ideation in less prevalent types of arthritis, such as RA. Data on medications and on prior suicide attempts were not available in the survey. Finally, the cross-sectional nature of the study precluded determination of causality.
In conclusion, suicidal ideation is prevalent among adults with arthritis and should be carefully evaluated by physicians. Depression and short duration of arthritis, binge drinking, income, and the presence of more than 3 comorbidities identified subgroups at greatest risk for suicidal ideation that should be the focus of prevention and intervention approaches.