Individual differences, mood, and coping with Chronic pain in Rheumatoid Arthritis: a daily process analysis

Abstract

This study examines individual differences in coping and associated health outcomes as they unfold across time. Twice daily for one week, 71 individuals with Rheumatoid Arthritis reported their pain, coping efforts, and negative mood via structured daily records. The five factor model of personality (neuroticism, extraversion, openness to experience, agreeableness, conscientiousness) and disease status were also assessed. Multi-level statistical models examining within and between person variability indicated significant temporal associations from coping to pain and bi-directional associations between mood and pain within days. Furthermore, findings suggest that coping use and coping effectiveness were moderated by personality. Implications for models of coping with chronic pain, as well as clinical applications, are discussed.

Keywords:

• Individual differences
• Mood
• Coping
• Rheumatoid arthritis

Acknowledgments

This manuscript is based on theses submitted by Sarah Newth to the Department of Psychology, University of British Columbia, in partial satisfaction of the requirements for the master's and Ph.D. degrees. The research was supported in part by pre-doctoral fellowships to the first author from the Social Science and Humanities Research Council of Canada and the British Columbia Health Care Research Foundation, and research grants to the second author from the Social Science and Humanities Research Council of Canada. The authors would like to thank Carole Bishop, Jennifer Campbell, Martha Capreol, Ken Craig, Melady Preece, and Tess O’Brien for their help. They would also like to thank the anonymous reviewers for their useful insights and suggestions for improving the manuscript.

Notes

¹ The following procedure was followed in regards to missing data for individual items at any particular timepoint within completed diaries. Indices for coping and mood scales were only calculated for each participant at each specific timepoint if they had reported on 50% or more of the items making up each particular index. For example, calculation of the negative mood index at a given timepoint required the participant to respond to at least 3 of each of the 5 mood items for depressed mood, anxious mood and angry mood respectively. Coping indices were only calculated for each participant at each specific timepoint if the same criteria were met (i.e., 50% or more of the items completed for each coping subscale at any given timepoint).

² For more detailed information regarding the linear equations and associated procedures used in the multi-level models, please contact the authors.

³ A follow-up analysis was conducted in order to examine whether the temporal associations between pain and mood were bi-directional. HLM analyses revealed that AM pain was significantly associated with PM mood within days (b = 0.06, t (441) = 2.20, p = 0.03), even after controlling for the highly significant effect of AM mood (b = 0.76, t (441) = 17.26, p<0.001).

⁴ Follow-up analyses were conducted in order to determine whether effectiveness of coping was moderated by mood or pain at the time of coping efforts (i.e., morning coping by morning mood interactions and morning coping by morning pain interactions). All AM coping by AM mood interactions (including emotional expression by mood) were nonsignificant in their associations with PM pain after controlling for the main effects of AM pain, AM mood, and the main effects for the other ways of AM coping. All AM coping by AM pain interactions were also nonsignificant after controlling for the main effects of AM pain, AM mood, and the main effects for the other ways of AM coping.

⁵ There are a number of differences between our study design and that used by Stone and colleagues that may have improved adherence rates in our study. Most importantly, the study design used here placed far fewer demands on participants. Research on adherence to medical regimens has suggested that the single most important way to improve compliance among patients is to decrease the numbers of times per day that patients need to complete their regimen (Eisen et al., 1990). In a review of the literature, Greenberg (1984) found that adherence rates for twice daily regimens were 18% higher than thrice daily regimens. In our study, participants completed diary entries twice daily for 7 days, as opposed to thrice daily for 24 days as was done in the studies by Stone and colleagues. These researchers also found significant fatigue effects among their participants, with rates of compliance significantly higher during the first week of the study than in later weeks.

Another notable difference between the design of our study and theirs is in the time at which participants were asked to complete the diary entries. We used mealtime (lunch time) and bedtime to serve as memory prompts, or signals, to the participants to complete their diary entry. Previous research on medication adherence has found timing, and lack of interference with one's regular schedule, to be critical to increasing adherence (e.g., Dunbar-Jacob et al., 2000). Stone and colleagues’ use of 10 a.m., 4 p.m., and 8 p.m. likely increased nonadherence because these times are not necessarily anchored to natural transition or “break” times for participants.

The precise timing of the diary entry was not critical to the research question being addressed in the present study, as it was in the Stone and colleagues’ studies. Rather than being told that data needed to be entered within a 30-min window, participants in the current study were told to complete the diary entries around lunch time and around bedtime. Rather than decreasing adherence, our experience is that this greater flexibility serves to increase the ease of participating in the study and of completing the diary and therefore to increase adherence.

Further, rather than providing group instructions in completing the diaries, we provided individually tailored instructions at the end of a one-to-one interview that was designed to increase interviewer–participant rapport, and thus improve compliance. Finally, Stone and colleagues paid their participants $150; participants in our study were unpaid volunteers who were interested in participating in a study about RA. When participants are paid a relatively large sum of money to participate in a study “voluntarily”, and many are unemployed, it may increase their motivation to merely say they completed their diaries on time, rather than to actually complete their diaries on time. In sum, it appears unlikely that the relatively high noncompliance rates reported in Stone and colleagues’ studies would apply to our study given the differences in methodology.