The results from this study show that the IOF-wrist fracture questionnaire has an adequate repeatability, since the kappa statistic was moderate to good for most questions and quite similar to data obtained with Qualeffo-41 [10
]. The interval of 2 weeks for test–retest repeatability may have negatively influenced the kappa statistic, as quality of life might change in these 2 weeks. The internal consistency was excellent as follows from the very high Crohnbach alpha, similar to that for Qualeffo-41 [10
The IOF questionnaire on distal radius fracture discriminated well between patients with distal radius fracture and controls, as can be concluded from the high odds ratios. Similar data have been obtained with Qualeffo-41 [10
]. The 12 questions discriminated to a similar degree between patients and control subjects, as should be expected, because the items were identified in a focus group of patients with wrist fracture. The discrimination was excellent on all questions, regarding upper limb symptoms, physical function and general health.
The 1-year follow-up in the patients with wrist fracture showed adequate responsiveness to change, since the median score of the IOF-wrist questionnaire decreased from 60 to 25 after 3 months and to less than 10 (on a scale of 100) within a year. The improvement was very rapid in the first 3 months after the fracture followed by a slower improvement up to 1 year. Whether improvement may still continue to occur after 1 year cannot be answered by this study. A similar course of improvement, i.e. fast improvement during the first 3 months, followed by a slower improvement to (almost) complete recovery at 1 year after the fracture, has been observed with other questionnaires and physical assessment, i.e. handgrip strength [13
]. As can be expected, fractures on the right side had a higher impact on quality of life than fractures on the left side. This effect was even more marked for the dominant versus non-dominant side. This confirms the face validity of the IOF-wrist fracture questionnaire.
Quality of life could not be measured before the fracture, but it is likely that it is similar or better than the estimate at 12 months after the fracture. The major decrease in quality of life was present during the first 6 months after the fracture. The loss of quality of life after wrist fracture may have been somewhat underestimated due to the exclusion criteria, since patients with comminuted fractures were excluded as well as patients with recent clinical vertebral fracture or other osteoporotic fracture. There was some loss to follow-up, which may also have influenced the results a little.
The utility loss after distal radius fracture was 0.14 during the first 3 months and 0.03 during the second 3 months assuming that utility was 0.80 at baseline similar to the value at 12 months. It indicates loss of QALY of about 0.09 during the first half year and 0.02 during the second half year. The total loss after wrist fracture adds up to 0.055 QALY. This result is similar to a previous study on quality of life after distal radius fracture [13
]. In the previous study, the total quality of life lost was 0.05 QALY. An expert panel of the National Osteoporosis Foundation (NOF) estimated the quality of life loss after wrist fracture at 0.0464 in the first and 0.0006 in the second year after the fracture [16
]. However, the QALY loss in the second year could increase to 0.30 in the case of dependency after the fracture according to the panel [16
]. Thus, the QALY loss may depend on the age of the patient, the type of fracture and complications such as complex regional pain syndrome, all causing dependency of the patient on others. A similar variation was reported by the panel of the NOF regarding quality of life loss in the first year after vertebral fracture, ranging from 0.05 in a vertebral deformation to 0.50 QALY in a clinical fracture with severe pain [16
]. Classification of vertebral fractures at diagnosis and a follow-up study on quality of life should be performed to better define the utility losses. The problem is that the onset of a vertebral deformity is often not known, as it may be asymptomatic.
Besides the new IOF instrument and the EQ-5D, other instruments have been used to assess recovery after wrist fracture. The disability of the arm, shoulder and hand (DASH) questionnaire, the patient-rated wrist evaluation (PRWE) and the short form 36 (SF-36) were combined with physical response measures in 59 patients with distal radius fracture [15
]. In this study, the questionnaires were highly responsive in the first 3 months after the fracture when physical testing was not possible. The PRWE was more responsive than the DASH, and these two were more responsive than the SF-36, which is a generic quality of life instrument. The PRWE is a specific wrist questionnaire and the DASH is an upper limb questionnaire. Another analysis came to similar conclusions [17
]. In our study, the specific IOF instrument was more responsive than the generic EQ-5D and the Qualeffo-41, which is a specific vertebral fracture questionnaire.
Strengths of our study include the design of our questionnaire after focus group interviews, the comparison with a generic instrument generating utility values and the longitudinal multicenter design. A limitation of our study is that the follow-up time points were not always strictly adhered at. However, when restricting the analysis to the subjects whose follow-up was within a strict time frame (e.g., 5–7 weeks for the 6-week time point), this did not change the results. Another weakness of our study is the fact that we did not compare our questionnaire with existing instruments such as DASH and PRWE. In addition, physical assessments such as handgrip strength were not done in our study.
In conclusion, the IOF-wrist fracture questionnaire appears to be a reliable and responsive quality of life questionnaire, showing sufficient repeatability, high internal consistency and adequate sensitivity to change. It is ready for use in patients with wrist fracture, preferably in combination with Qualeffo-41 for overall evaluation of quality of life with regard to osteoporosis.