Department of Psychiatry, University of Oulu and Oulu University Hospital, P.O. Box 5000, FIN-90014 University of Oulu, Finland and 1International University Bremen (IUB), School of Engineering and Science, D-28725 Bremen, Germany
Correspondence to:
M. Timonen. E-mail: markku.timonen{at}oulu.fi
We thank Dr Matsukawa for the interest in our article. In response to the specific points addressed by Dr Matsukawa, we have now made some additional analyses. First, none of the suicide victims in our database had suffered from systemic lupus erythematosus (SLE). However, it has to be remembered that all somatic diagnoses of suicide victims were based on hospital admissions extracted from the National Finnish Hospital Discharge Register. Thus, there remains the possibility that our data included some cases of SLE treated as out-patients, which were missed. Second, Dr Matsukawa wanted to confirm the order of onset of the diseases, i.e. whether rheumatoid arthritis (RA) preceded psychiatric disease, or vice versa. We have now performed further analyses specifically with regard to this question. We used subjects with osteoarthritis (OA) as the control group. However, of all the psychiatric disorders, only the information on hospital-treated depression was used, because depression is known to be a major risk factor in suicidal behaviour. Figure 1 shows the KaplanMeier estimates for the temporal relationship between first admission due to RA/OA and subsequent first hospitalization due to depression. In all cases with both RA and depression (n = 9), RA always preceded depression. Further, of all the cases with OA and depression, in 9 out of 12 cases depression followed OA. These analyses did not alter the major results of our paper, but actually provided us with important additional information in understanding the connection between RA and suicidal behaviour.
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