Background
Total hip arthroplasty (THA) has demonstrated among the most successful operations in medicine [
1,
2] and proven effective in patients with hip diseases [
3,
4], which has a profound impact on health-related quality of life (HRQoL) [
5]. For a better understanding of patient disorder severity and more appropriate therapeutic approach [
6], a large body of patient-based HRQoL questionnaires have been developed [
7], such as Copenhagen Hip and Groin Outcome Score (HAGOS) [
8]. This need has become more essential with the growing number of multicenter studies among different countries and cultures [
7], which provide more statistical power of evidence-based trials [
9]. When one reliable, valid questionnaire is used in populations with different cultures, it is necessary to test the psychometric properties of the questionnaire rather than simply translating the content to avoid bias due to cultural variety [
10,
11].
The HAGOS, published in 2012, consists of 37 items in six subscales: symptoms (7 items), pain (10 items), function in daily living (5 items), function in sport and recreation (8 items), participation in physical activities (2 items), and hip- and/or groin-related quality of life (5 items) [
8]. A Danish, English, Swedish, and Dutch version of HAGOS was distinguished in good reliability and validity [
8,
12,
13] and has been widely used in assessing patients with hip disorders. Chinese is the language spoken by the largest population in the world, and China has one of the largest population of patients performed with total joint arthroplasty and arthroscopy. However, there is no HAGOS in Chinese version for this population so far. Besides, as a scale evaluating hip problems, no study has been performed to validate HAGOS in arthroplasty patients.
Considering the cultural gap and social environment between China and western countries, the purpose of this study was to translate, adapt the original version of HAGOS into a Simplified Chinese version (HAGOS-C) cross-culturally, and evaluate the reliability, validity, and responsiveness of HAGOS-C in native Chinese-speaking patients who underwent THA.
Discussion
In this study, the English version of HAGOS was successfully translated and cross-culturally adapted into Simplified Chinese. The HAGOS-C had good reliability, validity, and responsiveness in evaluating patients who underwent THA in mainland China.
HRQoL questionnaires are very important and valuable in the quantification of patients’ function and data analysis among studies. Nowadays, with the invigorating strategy through science, technology and education, and greater science and technology input in China, the number of papers annually published in China is the second largest all over the world [
24,
26,
27]. Therefore, valid questionnaires are urgently needed to support this huge amount of clinical research.
In the process of translation and adaptation, authors strictly followed the standardized procedure listed in the literature. In item A5, “vacuuming” written in the original English version of HAGOS were less popular among Chinese and were adapted cross-culturally into “sweeping floors”. Interestingly, with the popularity of price-friendly “sweeping and mopping robot” in China, better examples listed in A5 in HAGOS-C might be explored to substitute “scrubbing and sweeping floors”.
A floor effect of 20.8% was observed in the subscale of PA in HAGOS-C, which was also detected in literature before [
8,
12,
13]. This relative high floor effect might be due to the following reasons. Firstly, there are only two items listed in this subscale, which makes it easy to choose both of the items with the lowest score. Besides, some of the patients who underwent THA suffered from end-stage hip diseases, which restricted patients from participation in physical activities naturally.
In our study, all subscales of HAGOS-C showed very good internal consistency (Cronbach’s alpha = 0.787–0.886) and test-retest reliability (ICC = 0.793–0.946). The results above were basically in agreement with the data reported by Thorborg et al. (Danish HAGOS), Thomeé et al. (Swedish HAGOS), and Brans et al. (Dutch HAGOS) [
8,
12,
13]. The ICC for the QoL subscale (ICC = 0.946) is the highest among all subscales, which might due to the fact that quality of life for patients changed with least possibility in the duration interval of 1 to 2 weeks among the perspectives assessed in HAGOS-C.
The correlation between the subscales of HAGOS-C and EQ-5D total score, EQ-VAS, as well as SF-36 subscales, was in accordance with our hypothesis. Almost all correlations between HAGOS-C subscales and EQ-5D total score, EQ-VAS, as well as SF-36 subscales, were significant, except the correlation between pain subscale of HAGOS-C and role-emotional subscale of SF-36. However, the r value for these correlations varied a lot. In our study, HAGOS-C subscales correlated better with the EQ-5D total score, EQ-VAS, and physical function, role physical, and bodily pain subscales of SF-36, whereas these correlations were weaker between HAGOS-C subscales and vitality, social function, role-emotional, and mental health subscales of SF-36. One possible reason might be that HAGOS-C was designed for the evaluation of function and symptoms in the hip and groin region, and vitality, social function, role-emotional, and mental health subscales of SF-36 indicated psychological or social state of patients, which could be affected by many factors other than physical situation and symptoms comparing with other scales of high correlation with HAGOS-C. Interestingly, the correlation between symptoms, pain, and sport/rec subscales of HAGOS-C and EQ-5D and physical function, role-physical, bodily pain, and general health subscales of SF-36 were the slightly higher other subscales of HAGOS-C. Likewise, this might contribute to the fact that symptoms, pain, and sport/rec subscales of HAGOS-C indicated direct symptoms of patients, which were affected more by the disease itself with less interference of other matters. All of these suggested satisfied divergent or discriminant validity for HAGOS-C in THA patients.
The responsiveness was tested to detect changes between the preoperative and 6-month postoperative conditions. As our hypothesis, SRM and ES were defined as large after 6 months of postoperative rehabilitation. This outcome is similar to some part of other versions of the HAGOS. The ESs for the change in the score on the Danish version of HAGOS were − 1.29 to − 0.60, 0.01 to 0.19, and 0.77 to 1.78, in “much worse” and “worse” group, “somewhat worse” and “not changed” and “somewhat better,” and “much better” and “better” group, respectively[
8]. Analogously, ESs on the Swedish version were − 0.44 to − 0.19, 0.23 to 0.54, and 1.07 to 1.87 in 20 points lower, ± 20 points, and 20 points higher of global perceived effect group, respectively [
13]. The ESs in our study was much larger than the first two groups in both of the studies above, but comparable with the third group in these two studies. In the original Danish study, authors included patients seeking medical care presenting with hip and/or groin who had received treatment for the symptom, and in the cross-cultural study on Swedish, patients requiring hip arthroscopy for femoroacetabular impingement were investigated. Meanwhile, only patients who underwent THA were included in our study. Under the circumstances, the patients’ symptom severity in both of the studies above was milder than our study. As we know, THA has demonstrated among the most successful operations in medicine [
1,
2], which has been proven effective in patients with hip diseases [
3,
4]; so, it is reasonable that larger ESs were shown among patients who underwent THA.
There are several limitations to our study. First, the sample was limited in size and may not fully represent the Chinese population. Second, although Simplified Chinese is the official language in China, China is a country with multiple nationalities, most of which have their own language. Thus, the problem of national cultural differences should be noted. Finally, patients with symptoms in the hip and/or groin region who were not performed with THA were not evaluated, which could be carried out in future studies.