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Significant Other Responses Are Associated With Fatigue and Functional Status Among Patients With Chronic Fatigue Syndrome

From the University of Washington, Seattle, WA.

Address reprint requests to: Karen B. Schmaling, Department of Psychiatry and Behavioral Sciences, Box 356560, Seattle, WA 98195-6560. Email: karens{at}u.washington.edu

	ABSTRACT

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION ACKNOWLEDGMENTS REFERENCES

 
OBJECTIVE: The predictive power of partners’ responses to illness behavior for illness outcomes was investigated among couples in which one person had chronic fatigue syndrome (CFS).

METHODS: One hundred nineteen participants who met case-definition criteria for CFS and were living with a significant other (SO) completed self-report measures of relationship satisfaction, responses of their SO to fatigue symptoms, and outcome measures of fatigue and functional status.

RESULTS: The results indicated that more frequent solicitous SO responses to illness behavior were predictive of greater fatigue-related severity and bodily pain. Solicitous SO responses to fatigue behavior were particularly influential in the context of a satisfactory relationship. In highly satisfactory relationships, solicitous SO responses were associated with significantly greater fatigue severity and fatigue-related disability than in relationships characterized by low or average satisfaction.

CONCLUSIONS: Solicitous SO responses to CFS-related symptoms are associated with poorer patient outcomes, especially in the context of a satisfactory intimate relationship. Because of the cross-sectional nature of the study, the direction of effects cannot be interpreted unambiguously. SOs may be inadvertently positively reinforcing illness-related behavior: Solicitous partners may help the patient more with tasks of daily living, thereby decreasing the patient’s activity level, which may lead to deconditioning and disability. Alternatively, patients with more severe symptoms and disability may present more opportunities for concerned SO responses, which again may be heightened in the context of a caring, satisfactory relationship. In either case, the results suggest that additional research on the role of solicitous SO responses is warranted.

Key Words: chronic fatigue syndrome • solicitousbehavior • couple • relationship satisfaction • outcome

Abbreviations: CFS = chronic fatigue syndrome; DSM-III-R =Diagnostic and Statistical Manual of MentalDisorders, third edition, revised; MAF = MultidimensionalAssessment of Fatigue; SF-36 = Medical Outcomes Study Short-Form36; SO = significant other; WHYMPI = West Haven-YaleMultidimensional Pain Inventory.

	INTRODUCTION

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Operant theory posits that certain responses by SOs to patient illness behavior may contribute to illness maintenance (1). Although the function of SO responses to illness behavior can only be ascertained by observing their effects on subsequent occurrences of illness behavior, certain SO behaviors are probably perceived as desirable or undesirable by patients. Solicitous SO responses to patient illness behavior, including encouraging rest and taking over tasks, may result in subsequent increases in illness behavior to the extent that these responses are desirable to the patient (ie, function as positive reinforcers). In the review that follows, it is evident that solicitous SO responses have been associated with poorer patient outcomes.

Much of the empirical work examining this model has used patients with chronic pain. For example, in one study, patients with chronic pain who were more satisfied with their social support exhibited more overt pain behavior, such as grimacing (2). In another study, the responses of partners of chronic pain patients to pain behavior were classified as solicitous, distracting, or punishing. More solicitous responses by the SO to pain behavior were associated with patient reports of higher pain intensity and lower activity levels (3). Kerns et al. (4) replicated and extended these findings, examining the effect of relationship satisfaction. They found a significant interaction between relationship satisfaction and solicitous responses: The most pain and inactivity were reported by patients who were satisfied with their relationships and who reported higher levels of solicitous responses by their SOs. These researchers also found that overt pain behaviors (eg, distorted ambulation and facial expressions) were significantly predicted by more solicitous and distracting partner responses, over and above the contribution of demographic and pain severity variables (5). The interaction of SO responses and relationship satisfaction is important to examine; relationship satisfaction may reflect the extent to which SO solicitousness occurs against the background of a desirable environment, potentially amplifying the reinforcing potency of solicitousness.

In addition to the research using self-report data, another set of studies has used direct observational measures of solicitous and aggressive partner responses to patient pain behavior. Romano et al. (6–8) compared the interactions of couples with and without one partner with chronic pain. They found that patients with chronic pain exhibited more pain behaviors and that their partners exhibited more solicitous behaviors than did partners in healthy control couples. Solicitous partner behavior also was more likely to precede and follow pain behavior among couples in which one partner had chronic pain than among healthy control couples. Solicitous responses to pain behavior predicted more physical disability among patients with chronic pain who were also depressed as well as among patients with greater subjective pain.

Like pain, fatigue is experienced privately and communicated socially; acute and chronic fatigue conditions may occur. CFS is characterized by at least 6 months of profound fatigue and other symptoms, including joint and muscle pain, headache, memory and concentration difficulties, unrefreshing sleep, sore throat, lymphadenopathy, and postexertional malaise (9). CFS is a diagnosis of exclusion requiring thorough medical, laboratory, and psychiatric evaluations to exclude conditions that could account for the CFS-like symptoms, such as hypothyroidism, human immunodeficiency virus infection, or bipolar affective disorder. CFS is associated with significantly impaired functional status (10). It is important to determine whether CFS-related outcomes are associated with specific SO behaviors or with relationship satisfaction, as has been found among partnered patients with chronic pain.

To date, only one study has examined the potential associations between the quality of CFS patients’ intimate relationships and the responses of their SOs to illness factors. A sample of 11 women with CFS completed daily activity and fatigue diaries and rated their relationship satisfaction (11). Fatigue ratings were unrelated to activity level among women dissatisfied with their intimate relationships. Among women with CFS who were satisfied with their intimate relationships, less activity (ie, more time spent reclining) was associated with higher fatigue ratings. These results suggest that, similar to Kerns et al.’s (4) findings in couples with chronic pain, inactivity and pain are more highly associated among patients with CFS in satisfactory relationships than among those in less satisfactory relationships.

The purpose of the present study was to apply an operant model of partner responses to illness behavior among couples in which one person had CFS to examine the relationship of these SO responses to fatigue-related illness outcomes. Specifically, it was hypothesized that more solicitous partner responses to illness behavior would be significantly associated with poorer patient outcomes and that this pattern would be more pronounced among couples in satisfactory relationships. Other forms of SO responses, such as distracting and punishing SO responses (eg, reading to or expressing anger at the patient, respectively) also have been investigated for their association with outcomes among patients with chronic pain. However, distracting and punishing SO responses have not been consistently related to patient outcomes in previous research, perhaps because punishment may produce short-term suppression but longer-term increases in illness behavior (6). In the present study, the associations of distracting and punishing SO responses with patient outcomes were examined without specific predictions. A cross-sectional design was used to determine whether the hypothesized associations were observed before an examination of the effects of SO responses over time was undertaken.

	METHODS

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Subjects
Participants were patients at the Harborview Medical Center/University of Washington Chronic Fatigue Clinic. All participants had completed a battery of self-report measures and laboratory and medical evaluations to rule out other causes of the CFS-like symptoms (9). Participants also completed a structured psychiatric diagnostic interview, the Diagnostic Interview Schedule for DSM-III-R (12). CFS was diagnosed according to the 1994 Centers for Disease Control and Prevention criteria, using specific self-report items regarding the pattern and timing of symptoms. Patients were also evaluated for the presence of fibromyalgia, a form of nonarticular rheumatism characterized by diffuse body pain and 11 or more of 18 specific tender points as specified by the American College of Rheumatology guidelines (13). Participants were excluded if they were not partnered, met criteria for fibromyalgia, or did not meet criteria for CFS. Thus, our sample consisted of all patients who were partnered (ie, married or living with a SO) and met criteria for CFS.

Measures
In addition to the diagnostic procedures described above, participants completed four self-report questionnaires. The first was part II of the WHYMPI (14). Whereas the original version of the WHYMPI asked about SOs’ reactions to pain, the version used in this study was modified slightly to be relevant to our patient sample by querying participants about the reactions of their SOs to "CFS-related symptoms (fatigue, pain, weakness, etc.)." Solicitous SO response items (six total) included "gives me medication," "takes over my chores," and "gets me to rest." Punishing SO response items (four total) included "expresses irritation at me" and "expresses anger at me." Distracting SO response items (four total) included "involves me in activities" and "talks to me to take my mind off the fatigue." Higher scores correspond to more of the specific type of reaction by the SO. Investigations of the validity of the WHYMPI scales in samples of patients with chronic pain and their partners have revealed small correlations (r = .22) between observed SO solicitous behavior and patient-reported SO solicitous behavior (7). However, correlations between SO responses on the WHYMPI and the corresponding scales based on patient perceptions of SO responses have been stronger (r = .38-.77) (3). Patient and SO perceptions of SO responses to patient behavior seem to have acceptable concordance; however, perceived SO behavior may be an important, but somewhat distinct, issue from actual behavior.

Relationship satisfaction was assessed by a single item that asked each participant to rate how happy he or she was with their relationship, with a seven-point response ranging from "extremely unhappy" to "perfect." This item was taken from the Dyadic Adjustment Scale (15), a widely used measure of satisfaction with one’s intimate relationship. This single item accounts for about 20% of the variance in the measure’s total score (16), providing an adequate estimate of relationship satisfaction.

Participants also completed two criterion measures, the SF-36 (17) and the MAF scales (18). The SF-36 is a 36-item instrument that yields scores on eight subscales of functional status, well-being, and quality of life: physical, emotional, social, and role functioning; bodily pain; mental health; vitality; and general health. For the present study, the physical functioning and bodily pain subscales were used as measures of illness-related outcomes. The physical functioning subscale assesses the participant’s ability to perform physical activities, including dressing, vacuuming, and climbing stairs. The bodily pain subscale reflects both pain severity and the degree to which pain interferes with normal activities. These subscales were chosen because of the focus of the study on limitations in physical functioning due to illness. Other SF-36 subscales were not included because of overlap with the MAF scales and because of "floor" effects and lack of score variability in CFS samples (10). All SF-36 subscale scores range from 0 to 100, with higher scores reflecting better functioning; scores of 80 or above are generally interpreted as indicative of normal-range functioning (17).

The MAF is a 16-item instrument that yields two scores, fatigue severity and fatigue-related disability (18). All items are rated on a 10-point scale ranging from 1 ("not at all") to 10 ("a great deal"). The fatigue-related disability subscale measures the degree to which fatigue interfered in the previous week with 11 routine chores or tasks (eg, "In the past week, how much has fatigue interfered with your ability to ... do household chores ... shop, and do errands ... ?"). The fatigue severity score is based on a two-item subscale of severity of fatigue experienced during the previous week. These items are "To what degree have you experienced fatigue?" and "How severe is the fatigue which you have been experiencing?".

Analyses
SPSS version 6.0 software was used for all analyses (19). Descriptive statistics were used to characterize the sample in terms of demographic and clinical characteristics. Internal reliability statistics (Cronbach’s ) were calculated for the modified and less-well-established instruments used in the study (WHYMPI and MAF) to examine scale integrity. A series of univariate analyses (bivariate correlations and t tests) were used to assess the relationship of each demographic variable (gender, age, employment status, and years of education), clinical status variable (current major depression), and SO variables (solicitous, punishing, and distracting responses and relationship satisfaction) to each of the four criterion variables (fatigue severity, fatigue-related disability, physical functioning, and bodily pain).

Hierarchical regression was used to evaluate the unique contribution of the SO variables to predicting each of the four criterion variables. First, the demographic and clinical variables that demonstrated a reliable univariate association with the criterion variable were entered in one block, before the additional contribution of the SO variables to the prediction of the criterion was evaluated with a stepwise procedure. A statistically reliable increase in the multiple correlation coefficient would indicate a unique contribution of the SO variable to outcome, over and above the contribution of the demographic and clinical variables.

To evaluate the moderating effect of relationship satisfaction on the association between SO response and outcome, the strength and nature of the relationship satisfaction-by-SO response interaction term was evaluated in the multiple regression after the data were centered, as recommended by Jaccard et al. (20).

	RESULTS

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Demographic and Clinical Characteristics
The sample was predominantly white (93%), female (76%), married (76%), well-educated (mean years of education, 14.3), and employed (51%). Eighteen percent (12%) met criteria for current major depression. Table 1 summarizes age, gender, ethnicity, education, employment status, marital status (married vs. living together), and frequency of concurrent major depression for the 119 patients with CFS in the sample.

Associations of Demographic and Clinical Status Variables With Patient Outcomes
Table 2 summarizes the univariate associations between the four outcome variables and the demographic and clinical status variables. Associations were evaluated with Pearson correlation coefficients for continuous measures (ie, age, education, and length of illness) and with t tests for categorical variables (ie, gender, current employment status, and current major depression).

Associations of SO Response and Relationship Satisfaction With Patient Outcomes
The correlations of the four outcome variables with the SO response variables and relationship satisfaction are shown in Table 3. Solicitous SO responses were significantly associated with fatigue severity and bodily pain; more solicitousness was associated with worse patient outcomes in both cases. Distracting and punishing SO responses were not significantly associated with any of the outcome measures. The continuous measure of relationship satisfaction was associated only with fatigue-related disability: Greater relationship satisfaction was associated with more fatigue-related disability.

The results were consistent with the results of univariate analyses in Tables 2 and 3. Employment and gender were selected in the prediction of physical functioning, and gender was selected in the prediction of fatigue-related disability. In the second step, none of the SO response variables were found to add to the prediction of physical functioning or fatigue-related disability. However, for fatigue-severity and bodily pain, SO solicitous responses were found to account for a significant proportion of the variance of these outcome measures.

Moderating Effects of Relationship Satisfaction
The moderating effect of relationship satisfaction on the association between solicitousness and outcome was evaluated by assessing the significance of the addition of the solicitousness-by-relationship satisfaction interaction term, using centered data (following Cronbach, Ref. 21). The solicitousness-by-relationship satisfaction interaction term did not significantly increase the explained variance in physical functioning or bodily pain.

For fatigue-related disability and fatigue severity, the interaction term significantly increased the explained variance over the regression model with only the main effects of solicitousness and satisfaction included (change in R² = .047, p = .019, and change in R² = .032, p = .049, for fatigue-related disability and fatigue severity, respectively).

To evaluate the nature of the moderating effect of relationship satisfaction, the regression coefficient associated with solicitousness was calculated at low (-1 SD), average, and high (+1 SD) levels of relationship satisfaction for the two outcome variables (20). This procedure allows an evaluation of the effect of solicitousness on outcome at different levels of satisfaction. These calculations are summarized in Table 4.

For fatigue-related disability, the table indicates that only the slope of the regression under high satisfaction conditions was reliably different than zero. Under high satisfaction conditions, for every additional unit of SO solicitousness there were 0.68 additional units of fatigue-related disability.

	DISCUSSION

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The results of the present study indicate that SOs’ responses to signs of fatigue are associated with fatigue-related outcomes among patients who meet case criteria for CFS. Furthermore, it seems that SOs’ solicitousness in particular is associated with poorer patient outcomes.

Simple bivariate correlations demonstrated an association between solicitous SO responses and patient outcomes. For all outcome measures, SOs’ solicitous responses were associated with worse outcomes, and these associations persisted in the multiple regression analyses even after the variance accounted for by demographic and clinical variables was removed. However, the results did not suggest a similarly strong association between outcomes and the other two SO response measures. None of the bivariate correlations between outcome measures and punishing or distracting SO response were statistically significant. A thorough multivariate evaluation of punishing and distracting SO responses was not undertaken because we used an empirically driven analytic strategy of testing only SO responses that demonstrated reliable univariate associations.

There was mixed evidence of a mediating effect of relationship satisfaction on the associations between SO solicitous responses and patient outcomes. Relationship satisfaction was significantly correlated with one of the outcome measures: Greater fatigue-related disability was associated with more relationship satisfaction. Thus, relationship satisfaction per se was not a robust predictor of patient outcomes. Our hypothesis that SO responses would be more strongly associated with outcome among patients in highly satisfactory relationships was supported for solicitous responses with two of the outcome measures, fatigue-related disability and fatigue severity (see Table 4). Our results suggest that relationship satisfaction is important in mediating the effects of solicitous SO responses to fatigue behavior on fatigue-related outcomes. Our pattern of results also suggests that the results may be limited to fatigue-related outcomes and not generalizable to more global measures of functional status.

Demographic and clinical characteristics also were associated with illness-related outcomes. In particular, male gender and employment were associated with better physical functioning. Employment was associated with less bodily pain and older age. These results are consistent with previous research using a different sample from the same clinic that was the source of participants in the present study (10).

The most notable limitation of the current research is its correlational design. As such, it is not clear to what degree fatigue outcomes are influenced by SO responses or to what degree greater fatigue behavior presents more opportunities for solicitous SO behavior. Observational data would facilitate the examination of behavioral sequences between patient and SO and represent a step toward characterizing the temporal and causal connections between fatigue behavior and SO responses (6). Alternatively, unrelated personal or environmental factors may influence patients’ fatigue behavior, which may in turn influence SOs’ responses over time. Another shortcoming is that previous research has indicated that observed SO behavior is only modestly associated with patients’ perceptions of SO behavior. Future research should examine the association between observed and perceived responses to fatigue behavior among couples in which one person has CFS, similar to the work of Romano et al. (7). Mood and/or illness can strongly influence the evaluation of others’ behavior (22) and may explain the modest association between observed and perceived SO responses in previous research. However, a post hoc analysis of the data in this study showed no difference in the level of solicitous SO responses as reported by depressed compared with nondepressed patients with CFS. These issues await clarification in future research.

Our findings of a positive association between solicitous SO behavior and illness outcomes must be viewed as preliminary. This study is the first to focus on the potential role of specific partner behaviors and the intimate relationship environment in CFS. The results support the notion that SO behaviors are potentially important variables uniquely linked to patient outcomes. One interpretation of our results is possibly supportive of an operant approach to understanding the social role of fatigue behavior. The pattern of results may be consistent with solicitous partner behavior acting as a perpetuating factor in CFS. Solicitous partners may inadvertently reduce patients’ opportunities to perform tasks of daily living, thereby decreasing patients’ activity levels, possibly leading to deconditioning and more disability. Alternatively, patients with more severe symptoms and disability may present more opportunities for concerned SO responses, which again may be heightened in the context of a caring, satisfactory relationship. Because of the cross-sectional nature of the study, the direction of effects cannot be interpreted unambiguously. In either case, the results suggest that additional research on the solicitous behaviors of SOs is warranted.

Descriptive research regarding the role of solicitous SO behaviors may have important implications for treatment. Chronic pain treatment programs based on an operant model have been effective in decreasing pain and medication intake and in improving emotional functioning (for a review, see Ref. 23). Operant programs emphasize the gradual enhancement of patient physical condition: increasing activity levels, teaching patients to express less pain behavior, and teaching their SOs to respond positively to active, functional behavior.

The most promising treatment for CFS seems to be cognitive behavior therapy. The results of medication trials have yielded disappointing results (24). Trials of cognitive behavior therapy for CFS (25, 26) have involved the patients’ SOs in an unstructured way. A useful area for future research would be to enhance cognitive behavior therapy protocols with the addition of a couple’s treatment component based on an operant model. The results of this study should not be interpreted to mean that SOs should not engage in any helpful behaviors. Rather, similar to operant-based chronic pain treatment programs, SOs should be encouraged to modulate solicitous responses to illness behavior and respond positively to patients’ efforts at paced, functional activity.

	ACKNOWLEDGMENTS

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This work was supported in part by Grant U19-AI38429 from the National Institutes of Health. The authors appreciate the comments of Dr. Joan Romano and four anonymous reviewers on an earlier version of this manuscript.

Received for publication February 22, 1999.

Revision received October 8, 1999.

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