Presented data show slightly higher SA rates (77.6%) than those reported in the literature (40-70%)7,24,25. This may be due to the fact that the patients of our sample come from a clinical population with distinctive characteristics compared to other populations of patients with BPD. The sociodemographic profile of the sample corresponds to patients who, due to the severity of their clinical course and difficulties in their treatment, are referred from other health areas to a Reference Unit in the treatment of patients diagnosed with BPD. Therefore, these are patients with BPD who have been on treatment for several years and who have already passed the onset and early stages of the disease. Their average age is thirty years, with an age range between seventeen and fifty-six years old. In the literature, studies predominate in patients with BPD who have had fewer years of treatment and with average ages closer to adolescence26,27. Precisely, some authors point out a specific functioning of BPD patients based on their age group28.
Regarding gender, 27.6% of the patients in our sample are men and 72.4% women. This corresponds almost exactly to the 1/4 ratio given by the DSM-529 and other review articles in high impact factor journals2,25,30. According to the data studied, being a woman is related to the presence of a greater number of SA. Classical studies and recent meta-analysis indicate that SA are more frequent in women, whilst completed suicide is more frequent in men6,31,32.
BPD patients generally show poor stress tolerance2,25. For some authors the most frequent stressors described by patients are those related to their work, like work overload, unemployment or job insecurity, which can trigger mental illness related to SB33. Moreover, frequent changes in employment are associated with a higher risk of SB in patients with BPD14. The data in our study indicates that having worked permanently compared to never having worked or having done it only occasionally is related to the presence and also to a greater number of SA. Also, being on sick leave is related to a higher number of SA according to the multivariate analysis performed using negative binomial regression. These results would be concordant with Nakao's findings in 201033, without any specific studies in BPD population done to date. Regarding unemployment data as a risk factor for suicide, there is controversy as some authors have described it as a protective factor against SB32.
We found that having siblings is significantly related to the history of having performed a SA. To our knowledge, this is a factor very little studied which could be interesting to investigate more deeply. BPD symptomatology is often shown in interpersonal and family contexts, with data suggesting that having siblings is related to more aggressiveness and problematic functioning, which are in turn related to SB34.
Another factor that increases the risk of a greater number of SA is having children. Poor stress tolerance presented by patients with BPD has been mentioned before and having children can be understood as an important stressor. BPD predisposes to a weaker psychological state in order to face the cognitive stress that entails having a child, which may trigger suicide attempts35.
Being admitted to hospital is another factor related to recent stress. This is significantly associated with a greater number of SA according to the present analysis. These data are coherent with those found in the literature, which affirm that the number of previous hospital admissions is related to a greater number of SA14,36. Furthermore, it has been established that the period following discharge from hospital is of special risk for SB37,38.
Preliminary studies from our research group have already spoken about history of trauma and its important relationship with SB, emphasizing the role of bullying19. The data is consistent with the literature reviewed and those expected in BPD population4,39,40. This is population particularly vulnerable to adverse events in childhood and the data studied support this significant relationship between trauma and SB in BPD, which in line with that has been described in recent studies9,17,18.
Different authors propose anxiety as the link between sociodemographic and/or clinical variables, such as the aforementioned history of childhood trauma and SB in BPD17,41. Hamilton Anxiety Rating Scale (HARS)42 has been widely used as a method of measuring anxiety. This anxiety-state scale evaluates its intensity in its psychological and physical aspects, as well as in its behavioral manifestations. Its items refer to at least the last three days prior to the interview, making it an evaluation of the patient's condition at the time the assessment is done43.
Suicide attempts of the patients with BPD studied are related to anxiety measured with the HARS both in the univariate analysis and in the multivariate analysis. Likewise, anxiety is also related to a greater number of suicide attempts according to the multivariate analysis performed using negative binomial regression. Anxiety is a symptom present in numerous psychiatric syndromes and in a nonspecific way in maladjustment situations attributable to pathological personality traits. The presence of psychopathology is the most important predictor of suicide after a history of previous SB16. This anxiety could thus increase the risk of suicide with a greater statistical strength than the BPD syndrome itself of which anxiety is part44.
Some patients with BPD have a high risk of SB since adolescence, either as an almost constant trait or because it is precipitated in "acute" risk periods2. In this last case, the acute precipitation of suicide attempts in patients with BPD may be the variable that most relates to positive scores on the HARS. It is associated through multivariate analysis with statistical significance both with the presence and the number of SA.
The main methodological limitation of the design of this study is that it is an observational, descriptive, retrospective and cross-sectional study of concurrent temporality. This design model does not allow to establish causal links between the associations found and does not have the statistical power that a prospective study could have.