Background/Purpose:

Rheumatoid arthritis (RA) is the most common chronic inflammatory arthritis and has a high standardized mortality ratio when compared to general population. One of the possible ways to assessing mortality is to use the death certificate (DC) that is nationally available and has a broad coverage and further continuity. The evaluation of multiple cause-of-deaths provides beyond the underlying cause of death, the understanding of whole context of death, by the recognition of non-underlying causes of death, which are very important in chronic diseases. The aim of study was to evaluate the mortality profile of RA using the multiple cause-of-death method.

Methods:

The DC is established according to World Health Organization recommendation and is composed by two parts: the first presents the sequence of events leading to death, with underlying cause of death stated at last line, and the second part is composed by contributing causes of death.

Death information was provided by the state public center responsible to receive the data from civil registry office. The data about the whole population were obtained from the site of public health care system. Were chosen DC which has had RA (ICD-10: all group M05, M06.1, M06.8 and M06.9) on any line of the medical certification. All DC (N=3938) age above 19 years, for the period of 1996 to 2010 on which RA was listed as an underlying (N=1091) or non-underlying (N=2847) cause of death were analyzed. The variables gender, age and cause of death were analyzed, as well as comparisons between the two sub-periods (1996 -2000 and 2006-2010).  To compare the proportional mention of causes of death between the sub-periods, we used chi-square test, performed at SPSS version 20.0. We set the level of significance at p < 0.05.

Results:

For RA as an underlying cause of death, 251 were males (M) and 840 females (F), with a ratio M/F of 1/3.3. The mean age of death was 67.12 (SD 13.32) years and the main non-underlying causes of death associated with RA were pneumonia (38.86%), septicemia (29.7%), interstitial lung disease (10.91%) and heart failure (9.17%). Comparing the sub-periods, there was an increase of infectious causes (pneumonia and septicemia) and a reduction of heart failure, while interstitial lung disease remained stable. 

For RA as a non-underlying cause of death, the mean age of death was 67.92 (SD 13.03) years, with 672 males and 2175 females and a sex ratio of 1/3.2. The most common underlying causes of death were circulatory (35.16%) and respiratory system diseases (21.81%). Comparing the two sub-periods, there was a decrease in respiratory system (all group), pneumonia and cerebral infarction, but an increase in interstitial lung disease in more recent period.

There were 19 cases of tuberculosis (3 as non-underlying and 16 as underlying cause-of-death), but without any type of predominance.

Conclusion:

The cardiovascular (CV) disease remains as an important cause of death in RA, justifying a judicious follow-up and treatment of CV risk factors. The infectious diseases are an increasing cause of death in RA patients, bringing the question if infection is related with the vigorous immunosuppressive treatment.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-multiple-cause-of-death-study-in-rheumatoid-arthritis/