Department of Nursing, Dalin Tzuchi Hospital

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by inflammation and progressive damage of the joints that affects 0.5-1.0% of the population worldwide. It usually occurs in individuals who are 30 to 50 years-old, and about 20-30% of affected individuals exhibited some arthritis-attributable work limitations, thereby posing major burdens to patients, families and social care systems.

In light of the increasing threat of RA, optimal management of RA may improve clinical outcome and decrease mortality, thus resulting in reduced hospitalization and medical cost. Recently, case management (CM) has drawn more attention in medical practice as an approach to such a high-cost and high-risk chronic disease. European league against rheumatism (EULAR) further launched that the involvement of CM, which was delivered by the trained nurse, in the management of chronic inflammatory arthritis to achieve favorable prognosis. Consequently, there has been increased attention to the influence of CM among arthritis patients. Nevertheless, the corresponding effects still remained conflicting.

Of the studies conducted thus far, the investigators found that the majority of these studies were conducted in Western populations. Information on whether the CM delivered by the nurses could influence the clinical outcomes for RA patients in Taiwan was still limited. To narrow this gap in the literature, the present study aimed to clarify the long-term effectiveness of CM through NLC for RA patients by using generalized estimating equations (GEEs), with the intent that the findings could serve as a reference for providing empirically robust grounds for healthcare providers to formulate some care programs that are culturally appropriate for Asian RA patients.

Methods Study design and subjects A quasi-experimental pre-posttest control group design, with purposive sampling, will be used to recruit participants from the Rheumatologic department of a hospital in southern Taiwan from July of 2016 to June of 2017. The inclusion criteria were (i) being at least 20 years old at the time of recruitment (ii) having no cognitive impairment and severe complications, (iii) being able to express opinions in either Mandarin or Taiwanese, and (iv) having a diagnosis of RA. To ensure participants' anonymity, all questionnaires were marked with an encryption code to facilitate data analysis, but with no personal identifiers.

Sample size calculation Sample size calculation for this analysis of repeated measures to detect an effect size of 0.2 at 80% power and a 0.05 significance level indicated that a sample size of 68 patients is needed (according to G- POWER 3.1 analytical software, Franz Faul, Universitat Kiel, Germany). A sample of at least 90 participants for both groups combined was required on the basis of these parameters, allowing for a 30% attrition rate.