This study retrospectively analyzed the prognosis of 67 RA patients after ICU admission and identified the predictive factors of 30-day mortality. We revealed that the prognostic factors of 30-day mortality for RA patients included high prednisone dose, high APACHE II score, and prolonged PT-INR at ICU admission.
Previous studies have examined the risk factors and mortality of RA patients after ICU treatment 6−9, 11−15, 17, 25, 26. The short-term fatal outcome of RD, including RA, tended to be worse in RA patients than in the general population 9, 17, 25, and the long-term (1–3 years) mortality of RA patients was significantly increased after ICU admission 8, 25. In our institution, the 30-day, 90-day, and 1-year mortalities after ICU admission were 21%, 27%, and 37%, each. This is likely due to the tertiary nature of our hospital and because our study design excluded mild cases. Furthermore, Peschken et al. reported that the most common reasons for ICU admission were CVD and infection 8. A French cohort study involving patients with RD demonstrated that infection and RD exacerbation were the most common causes for ICU admission 13. Barrett et al. reported higher rates of severe sepsis and poorer prognosis in RA patients than in the general population 25. RA patients have an increased a risk of infection 2−4, 15, 17. A previous study demonstrated that the risk factors for the ICU admission of RA patients due to infection included the non-use of csDMARDs, old age, and comorbidity with COPD or CKD 15. The current study found that the majority of the 30-day mortality group admitted to our ICU due to infection was nonsurvivors. Immunosuppressive treatment, including bDMARDs, csDMARDs, and glucocorticoids, is reportedly associated with infection 15, 27−32, whereas the use of bDMARDs and/or csDMARDs was not found to be a risk factor for mortality. In line with previous reports, multivariate analysis showed that the dose of prednisone was a strong risk factor in the 30-day mortality group in our study 6, 15, 17, 29, 32, 33. Treatment with glucocorticoids increased the incidence and hazard of adverse effects in RA patients, such as diabetes mellitus, osteoporosis, thrombotic stroke, CVD, serious infection, and death 34−36. Two studies previous showed that the use of glucocorticoids for RD led to poorer prognosis in short-term outcome after ICU admission 26, 37. Therefore, our findings in RA patients indicate that the use of higher prednisone doses may be a risk factor for short-term mortality in these patients. Increased doses of prednisone may have been used in patients with higher disease activity who could not be treated with csDMARDs and/or b/tsDMARDs; however, we were unable to accurately analyze disease activity in patients because of disturbed consciousness or intensive care. Several studies have reported high disease activity and early presence of joint damage as poor prognostic factors for RA 38−40. Therefore, it seems reasonable to treat patients with DMARDs and avoid the use of glucocorticoids as possible. In this study, most of the patients with RA (79%) had been treated with glucocorticoid due to various severe complication, such as heart, liver, and renal failure, suggesting that the patients who had been hard to decrease the amount of glucocorticoid for their disease activity and severe complication might be poorer prognosis of 30-day ICU survival.
RA patients often have several comorbidities, and previous studies have reported the risk factors for ICU admission and mortality, such as pulmonary disorder, renal dysfunction, and hypertension 6, 13, 15. To evaluate comorbidities, we calculated the updated CCI, which can be used to predict hospital mortality 20. Univariate analysis showed that the updated CCI, particularly the liver and renal failure scores, was higher for nonsurvivors in the 30-day mortality group than for survivors (Table 2) 6, 13, 15, 17. In the current study, the majority of RA patients were treated with mechanical ventilation and vasopressor therapy after IUC admission. Similar to another study 12, there was a significantly greater use of renal replacement therapy in the nonsurvivors of the 30-day mortality group than in the survivors. Renal replacement therapy was frequently used for worsened liver failure and renal disease among comorbidities and was increased in the nonsurvivors of the 30-day mortality group. Together with the findings from previous reports 12, 41, our data indicate that ICU patients requiring renal replacement therapy showed poorer prognosis. Previous studies reported that other organ replacement therapies, including mechanical ventilation and vasopressors, were associated with a higher mortality in the ICU population 12, 17, 37, 42, 43. By contrast, the present study did not find any difference in the 30-day mortality groups probably because our study only included RA patients and did not include those with other collagen diseases, such as systemic lupus erythematosus, dermatomyositis, Sjögren’s disease, progressive systemic sclerosis, mixed connective tissue disease, or vasculitis.
Some studies have reported that the prognostic factors of ICU mortality in patients with RD included high APACHE II and SOFA scores, serious infection, mechanical ventilation, vasopressor, renal replacement therapy, and glucocorticoid dose 6, 7, 9, 11, 12, 17, 26. In the present study, multivariate analysis showed that the predictive factors for prognosis in RA patients admitted to the ICU were use of higher prednisone doses, elevated APACHE II score, and prolonged PT-INR. Previous studies in the general population reported that APACHE II and SOFA scores were predictive factors of ICU mortality in RA patients 6, 7, 11, 12, 14, 21. Considering that the APACHE II scores of RD patients were shown to be approximately equal to those of the general population 14, 17, the results of the current study show that the APACHE II score in RA patients was also a prognostic factor of ICU mortality. Blood test analysis showed that coagulation abnormalities were a prognostic biomarker associated with poor outcome in all ICU mortality 44. Multivariate analysis showed that prolonged PT-INR at ICU admission could predict ICU mortality by using a routine coagulation test. Therefore, PT-INR should be extended to the ICU admission of patients treated with an anticoagulation agent for their comorbidity. The DIC scores and PT-INR on the day after ICU admission were significantly elevated in the nonsurvivors of the 30-day mortality group, thus suggesting that PT-INR, as a representative of DIC, is a useful biomarker for ICU survival.
This study has several limitations. First, clinical data were retrospectively analyzed. Second, this study used a small cohort from a single institution and did not include a control group. However, the characteristics of the patients treated at the ICU vary between different institutions. Our study was able to analyze an RA population with more critical comorbidities and complications because our institution treated patients with more severe disorders, such as organ transplantation, compared with other institutions around this area. Third, we did not analyze the disease activity of all RA patients, and this approach may have affected the interventions and outcomes of the patients. However, it was difficult to identify disease activity because our study included patients with impaired consciousness and/or are immobile.