The assessment of fatigue: Psychometric qualities and norms for the Checklist individual strength

OBJECTIVE

The Checklist Individual Strength (CIS) measures four dimensions of fatigue: Fatigue severity, concentration problems, reduced motivation and activity. On the fatigue severity subscale, a cut-off score of 35 is used. This study 1) investigated the psychometric qualities of the CIS; 2) validated the cut-off score for severe fatigue and 3) provided norms.

METHODS

Representatives of the Dutch general population (n=2288) completed the CIS. The factor structure was investigated using an exploratory factor analysis. Internal consistency and test-retest reliability were determined. Concurrent validity was assessed in two additional samples by correlating the CIS with other fatigue scales (Chalder Fatigue Questionnaire, MOS Short form-36 Vitality subscale, EORTC QLQ-C30 fatigue subscale). To validate the fatigue severity cut-off score, a Receiver Operating Characteristics analysis was performed with patients referred to a chronic fatigue treatment centre (n=5243) and a healthy group (n=1906). Norm scores for CIS subscales were calculated for the general population, patients with chronic fatigue syndrome (CFS; n=1407) and eight groups with other medical conditions (n=1411).

RESULTS

The original four-factor structure of the CIS was replicated. Internal consistency (α=0.84-0.95) and test-retest reliability (r=0.74-0.86) of the subscales were high. Correlations with other fatigue scales were moderate to high. The 35 points cut-off score for severe fatigue is appropriate, but, given the 17% false positive rate, should be adjusted to 40 for research in CFS.

CONCLUSION

The CIS is a valid and reliable tool for the assessment of fatigue, with a validated cut-off score for severe fatigue that can be used in clinical practice.

Chronic fatigue in type 1 diabetes: highly prevalent but not explained by hyperglycemia or glucose variability

OBJECTIVE Fatigue is a classical symptom of hyperglycemia, but the relationship between chronic fatigue and diabetes has not been systematically studied. We investigated prevalence, impact, and potential determinants of chronic fatigue in patients with type 1 diabetes mellitus (T1DM). RESEARCH DESIGN AND METHODS Out of 324 randomly selected T1DM outpatients, 214 participated in this cross-sectional observational study. Participants were compared with age- and sex-matched population-based controls. Chronic fatigue, functional impairments, current health status, comorbidity, diabetes-related factors, and fatigue-related cognitions and behaviors were assessed with questionnaires, and HbA1c values and comorbidity were assessed with medical records. Sixty-six patients underwent continuous glucose monitoring combined with an electronic fatigue diary for 5 days. Acute fatigue and four glucose parameters were determined: mean, variability, and relative time spent in hypoglycemia and hyperglycemia. RESULTS T1DM patients were significantly more often chronically fatigued (40%; 95% CI 34-47%) compared with matched controls (7%; 95% CI 3-10%; P < 0.001). Chronically fatigued patients had significantly more functional impairments. Fatigue was the most troublesome symptom. Age, depression, pain, sleeping problems, low self-efficacy concerning fatigue, and physical inactivity were significantly associated with chronic fatigue. Chronically fatigued patients spent slightly less time in hypoglycemia (proportion 0.07 ± 0.06 vs. 0.12 ± 0.10; P = 0.025). Glucose parameters were not related to acute fatigue. CONCLUSIONS Chronic fatigue is highly prevalent and clinically relevant in T1DM. Its significant relationship with cognitive behavioral variables and weak association with blood glucose levels suggests that behavioral interventions could be helpful in managing chronic fatigue in T1DM.

Heightened sensitivity to punishment and reward in anorexia nervosa

OBJECTIVE

The aim of this study was to investigate reinforcement sensitivity in anorexia nervosa (AN). It was tested whether self-reported punishment (PS) and reward sensitivity (RS) differed between adolescents with AN and healthy controls, and/or between AN-subtypes. In addition, the predictive validity of PS and RS was examined for AN symptoms one year later.

METHOD

In total, 165 female adolescents admitted for treatment of AN or eating disorder not otherwise specified resembling AN and 72 controls participated in the study. Participants completed measurements for eating disorder severity and the Sensitivity to Punishment/Sensitivity to Reward Questionnaire (SPSRQ). Percentage of underweight and severity of AN symptoms were measured again after one year in individuals with AN.

RESULTS

Individuals with AN scored higher on PS and RS than controls. In addition, the AN purging type showed higher PS than the AN restrictive type, whereas there were no differences in RS between AN-subtypes. Regression analyses indicated that PS and RS were independently associated with the degree of eating disorder symptoms, whereas only PS was related to percentage underweight. Yet, neither RS nor PS were related to percentage of underweight and AN symptoms after one year.

DISCUSSION

Although the present study clearly demonstrated that heightened punishment and reward sensitivity are both linked to AN, there was no evidence that these characteristics are also involved in the course of AN symptoms.

Severe fatigue after kidney transplantation: a highly prevalent, disabling and multifactorial symptom

Fatigue is a common symptom of patients with chronic kidney disease, but seldom investigated after transplantation. We determined the prevalence, impact and related factors of severe fatigue in kidney transplant recipients (KTRs). Medical records and questionnaires were used to assess kidney function, donor characteristics, fatigue (Checklist Individual Strength), functional impairments (Sickness Impact Profile), work status, body mass index (BMI), pain, depressive symptoms, social support and sleeping problems in 180 participating KTRs. KTRs were compared with sex- and age-matched population-based controls. KTRs were significantly more often severely fatigued (39%) compared to matched controls (22%; P = 0.001). Severely fatigued KTRs had significantly more functional impairments than nonseverely fatigued recipients (effect size ≥ 0.7) P < 0.001, and less often a paid job (27% vs. 48%, P = 0.005). Univariate analysis showed that severely fatigued KTRs received more often a kidney from a deceased donor, had a higher BMI, more pain, discrepancy in social support, depressive symptoms and sleeping problems. In a multivariate analysis (n = 151) the latter two associations remained significant. Severe fatigue is a highly prevalent and disabling symptom in KTRs. Moreover, severe fatigue after kidney transplantation is more strongly related to behavioural and psychosocial factors than specific transplantation-related factors. Findings have implications for fatigue management.