Differences and common ground in the frameworks of health-related quality of life in traditional Chinese medicine and modern medicine: a systematic review

Health-related quality of life (HRQoL) is about how people perceive their own health. The instruments used to measure it, even in China, are mostly devised in the West. However, it is increasingly understood that cultural distinctions might impact how we understand HRQoL, causing doubts about whether Western tools accurately represent this concept. This suggests that instruments created in the West might not fully grasp the health experiences of people in China, considering their unique cultural background. This systematic review study tries to understand from the literature how Chinese people think about HRQoL. It found two different ways of thinking about it: one based on modern medicine and the other on traditional Chinese medicine. Surprisingly, these ways of thinking lead to similar ideas about HRQoL. This study demonstrates the adaptability of HRQoL instruments across cultural settings with minimal adjustments. This challenging the notion that diverse cultures yield entirely distinct perspectives on HRQoL.

Health-related quality of life (HRQoL) is a multi-dimensional concept. Despite the challenge of defining HRQoL, there is a broad consensus that HRQoL focuses on revealing people’s subjective evaluation of health [1‐4]. Obtaining HRQoL information is crucial for comprehending patient health, making informed medical decisions [5, 6], evaluating healthcare interventions, guiding public health policies, and ultimately contributing to evidence-based medicine [7‐9]. Some HRQoL outcomes are preference-based, informing decisions on health products, technologies, and policies through QALY calculations [7]. Note that in this paper, we focus on HRQoL, rather than quality of life (QoL) in general.

The way we conceptualize HRQoL determines the specific health facets that we include in HRQoL measurements. To ensure valid and reliable HRQoL observations, standardized instruments are utilized. However, the recognition of cultural influences on HRQoL conceptualization has led to discussions about the suitability of Western-developed HRQoL measures in China [10, 11]. Specifically, when Western instruments, grounded in a distinct cultural context, are applied to measure HRQoL in China, dimensions important to the Chinese population's understanding of health might be overlooked or not accurately captured. This misalignment can lead to an incomplete representation of the true HRQoL experienced by Chinese individuals [12].

For example, Prior et al. found that participants from Cantonese-speaking communities in England described HRQoL using facets related to traditional Chinese medicine (TCM), such as ‘demons’, ‘food’, and ‘weather’, alongside common Western facets [13]. Similarly, a Q-methodological study emphasized the importance of 'spirits' and 'body constitution' in describing HRQoL among Chinese living in China, which were often absent in commonly used instruments [11]. Additionally, Mao et al. compared Western and Chinese-developed HRQoL instruments and identified exclusive HRQoL domains in China, including ‘emotion control’, ‘weather adaption’, ‘social adaption’, ‘spirit’, and ‘complexion’ [8]. These new aspects of Chinese HRQoL appear to be linked to TCM, indicating that TCM could influence how people perceive and describe HRQoL. Alternatively, it's possible that the Chinese perspective on HRQoL shapes practices within TCM. Thus, it can be argued that Western-developed instruments may inadequately capture the health experiences of Chinese populations within their cultural context, for instance in neglecting the influence of TCM [8, 10, 14]. Consequently, using Western-developed HRQoL instruments to assess HRQoL in Chinese populations may not yield optimal results if there are conceptual differences between Western and Chinese perspectives [10, 12].

Despite debates regarding the applicability of Western HRQoL instruments, the influence of culture on HRQoL conceptualization and instrument development remains unclear [15]. In China, efforts have been made by the scientific community to define HRQoL within a Chinese cultural context and use it to guide instrument development. However, there has been no systematic assessment, comparison, or synthesis of these Chinese-specific definitions or instruments. Consequently, it is still unclear how HRQoL is defined in China, and how these ‘Chinese definitions’ differ from those used in imported HRQoL instruments. This study aims to systematically review published studies that describe the theoretical and operationalised conceptualization of HRQoL. The objective is to explore and synthesize perceptions of HRQoL within a Chinese cultural setting.

This systematic review followed the guideline of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [16], including the following four parts: search strategy, identification and selection, data extraction and quality assessment.

After removing duplicates, a total of 6437 English articles and 6169 Chinese articles were identified through database searches. Following title and abstract screening, 33 English studies and 87 Chinese studies remained. Full-text selection further reduced the number to 6 English articles and 25 Chinese articles. The detailed information of the included paper was provided in Appendix 2. The selection process was illustrated in Figs. 1 and 2 of the PRISMA flow charts.

During full-text review, the 31 included papers were primarily divided into two categories: focusing on general definitions of HRQoL and frameworks of HRQoL. Among them, 14 papers focus on providing a general definition of HRQoL, 11 papers delve into HRQoL frameworks, while 6 papers contain information pertaining to both the general definition and the framework. Additionally, a distinction was made between studies based on TCM perspectives and those using the perspective of modern medicine (MM). The categorization of each paper was provided in Appendix 2.

This paper aims to explore and synthesize perceptions of HRQoL within a Chinese cultural setting. Our systematic review of relevant research reveals that two distinct perspectives existed in defining the conceptual frameworks of HRQoL in China: TCM and MM. To provide a comprehensive overview of these perspectives, we summarized the conceptual frameworks of both perspectives.

Firstly, it is challenging to define HRQoL. Mayo et al. proposed distinguishing between QoL and HRQoL [43]. However, Chinese studies often use the WHO's definition of 'health' instead of Mayo's HRQoL definition. The Chinese studies used the WHO’s definition of 'health' for defining HRQoL and also used the WHO definition of 'health' for the development of HRQoL instruments [10, 18, 19]. Meanwhile, examining HRQoL from TCM perspective reveals a focus on broader QoL aspects. TCM's emphasis on 'a balance between oneself and the environment' relates more to QoL than the narrow 'impact of disease and treatment' in the HRQoL definition from Mayo.

The two frameworks exhibit certain differences. On the level of concepts, TCM takes a holistic view, emphasizing the interconnectedness and interaction between body and mind, while MM does not. TCM framework uses terms like 'unity' and 'harmony' to underscore this holistic perspective and interaction, considering the inseparability of body and spirit [34]. By contrast, MM seems to be influenced by the theory of 'mind–body dualism,' separating the mind and body. According to the MM framework, individuals consist of two separate substances: body and mind, which can be described independently. As a result of these fundamental differences, the descriptions of HRQoL from these two frameworks consistently differ. Notably, though the HRQoL conceptual framework of TCM emphasizes the unity of health, instruments developed based on this conceptual framework often do not fully capture this unity. For instance, the Chinese Medicine Quality of Life-11 Dimensions (CQ-11D) emphasizes the unity of body and spirit but it still measures ‘body and ‘mind’ as two independent dimensions [33]. Therefore, we have observed that the idea of 'holistic' is difficult to embody in TCM instruments. This can be seen in Fig. 3.

Differences in specific facets describing HRQoL are also evident (Fig. 5). The TCM framework incorporates unique diagnostic indicators, many of which are specific to TCM-related 'symptoms' such as 'defecation' and 'spirit of eyes'. In contrast, MM focuses on measurable physical phenomena like 'vision' and 'weight'. Our analysis highlights two main reasons for these differences. Firstly, TCM places emphasis on 'image thinking' [44, 45], which involves intuitively grasping the abstract meaning of the world and its universal connections through intuition, metaphor, symbol, association, and analogy [45‐47]. TCM employs various 'images,' such as tongue image, pulse image, and syndrome image [47]. Based on this idea, TCM generally collects patients' symptoms through ‘making observations, listening to breathing, asking about symptoms and taking the pulse (the four fundamental methods for diagnosis in TCM)’ for analysis and syndrome differentiation. However, MM focuses on analysing pathological mechanisms using objective and measurable examination results [48]. Secondly, the discrepancy in specific facets is related to a well-accepted concept known as sub-health, which refers to a state between illness and health [49, 50]. Sub-health is characterized by experiencing different types of symptoms, both physical (e.g., pain, discomfort, fatigue) and mental (e.g., negative emotions, poor memory, inattention), for more than three months without any clear clinical attribution [51, 52]. In MM, there is no specific diagnose for such health status specific diseases when individuals experience prolonged fatigue despite normal clinical indicators. However, TCM theories have significantly contributed to the widespread recognition and acceptance of the sub-health concept.

Despite some differences, these two conceptual frameworks also share similarities. As mentioned before, while each framework has its unique facets, there is a significant overlap between them, as shown in the middle section of Fig. 5. This overlap may be inherent to TCM and MM, but can also be the result ‘borrowing’ aspect of TCM into MM and vice versa. The integration of these two frameworks can be observed in Fig. 5. MM also acknowledges the interconnectedness and interaction of body and mind when considering HRQoL. For instance, in the MM framework, there are facets that resemble TCM facets, such as 'complexion', 'energy', and 'constitution'. Similarly, in the TCM framework, facets emphasized by MM seem to be borrowed, like 'self-care' and 'mobility'. Among the shared facets, we found that 'appetite', 'sleep' and 'energy' were the most frequently mentioned facets in both frameworks. These can be considered vital elements in how people in China define HRQoL. The importance of 'appetite' can be attributed to various factors, including China’s historical experiences with varying food supply and the social aspect of eating [53]. For example, sharing meals serves as a common way for people to establish and express connections with one another in China. Additionally, 'sleep' was also recognized as an essential facet in most HRQoL instruments within the Chinese cultural setting. TCM regards 'sleep' as crucial for well-being and preventing illness [54‐56]. Compared to TCM, MM only recently acknowledges that sleep is vital for cognitive function, emotion, memory, endocrine balance, and immunity [57]. Furthermore, 'energy' was also frequently mentioned and covered by the two frameworks. In Chinese culture, 'energy' is closely related to the concept of 'Qi' (also spelled chi) in TCM [58, 59]. Qi is believed to exist in all things, including air, water, food, and sunlight, and is often translated as 'vital energy'—a fundamental substance that builds and sustains the body [60]. Furthermore, it is important to recognize that concepts from two types of frameworks are divided into 'domains', and these domains exhibit considerable overlap (Figs. 3, 4). These figures demonstrate that both frameworks describe HRQoL from four aspects: physical, mental, social, and adaptability to the natural environment. Although the theoretical basis and classification of the two frameworks may differ, the content is quite similar.

Although there are many overlapping facets between two frameworks, we still chose to describe HRQoL using two separate frameworks rather than combining them into one in this article. There are three main reasons: firstly, the original intention was to provide a comprehensive understanding of HRQoL in Chinese cultural. After a systematic literature review and content classification, we found that presenting two conceptual frameworks from different perspectives better represents the definition of HRQoL in China. Secondly, both frameworks have unique facets that cannot be merged. TCM includes facets such as 'urinate', 'stool', and 'spirit of eye', whereas the MM-based framework includes 'body weight', 'dependence on medication', and 'burdens to others'. Thirdly, even for overlapping facets, they have different classifications in each framework due to distinct theories. For example, 'emotions' holds different positions in the two frameworks. In TCM, it is considered a 'concept' contributing to overall health, ranked alongside 'the unity of form and spirit' and 'the unity of man and nature'. In MM, 'emotion' is a domain under the concept of 'mental health'. This divergence arises from MM viewing emotions as only a component of mental health, while TCM recognizes that emotions not only affect an individual's mental state but also have specific relationships with different organs in the body. As a result, TCM emphasizes the importance of maintaining emotional stability and avoiding extreme emotions for good health, leading us to list it separately in the TCM framework.

However, it would be beneficial to integrate these frameworks in future research. This integration aligns with the strategy of 'integrating Chinese and modern medicine', which is widely practiced in clinical practice in China. Integrative medicine, with its efficacy and complementary advantages, has emerged as one of the major medical systems alongside MM and TCM [61]. In Chinese clinical guidelines, it's common to find a combination of conventional disease diagnoses and traditional syndromes. While there are globally recognized standards for diagnosing diseases (such as the International Classification of Diseases, ICD-10), there's also an emphasis on identifying syndromes that reflect traditional Chinese characteristics [61]. Supported by the government policy, 'integrating Chinese and modern medicine' will continuously be the trend and our results also support this conclusion. It is evident that in the Chinese context, the definition of HRQoL cannot be adequately captured from a single perspective alone. Therefore, future research should aim to integrate the two HRQoL frameworks to provide a more comprehensive understanding.

The conclusion evokes questions whether we need a specific Chinese HRQoL instrument or if existing ones are sufficient. While instruments focused on 'Integrating Chinese and Modern medicine' naturally differ from Western-developed ones, it's important to assess if they truly benefit Chinese researchers internationally. We need to consider if a 'real Chinese HRQoL instrument' would be valuable outside of China, which could potentially devalue research from China and contradict the findings of the present study. Despite China having two well-developed HRQoL concepts, one possibly unique to China, they seem quite similar in terms of their main ideas.

As mentioned in the methods section, a limitation is the absence of a quality evaluation for the included articles. The second limitation is the inherent subjectively in classifying the concepts, domains and facets. In order to address this, we will employ 'concept mapping' in the future to provide a more objective exploration of the overlap in dimensions and facets between MM and TCM. The third limitation is that our research only included the general population and generic questionnaires. Patient-Reported Outcomes (PROs) are often diseases specific, such as cancer [62], but we were limited in the use of them due to the variance in patient groups, which would in turn impact how HRQoL is defined. However, this does not imply that PROs cannot be investigated. One potential solution could be to categorize specific disease groups. For instance, several authors have examined the applications and characteristics of PRO instruments as primary and secondary outcomes in randomized clinical trials in China [63], as well as the use of PROs in clinical trials of TCM [64] to promote and standardize PROs in China.

The present study is the first systematic review summarizing the conception of HRQoL in the Chinese cultural setting. We found two distinct frameworks of HRQoL exist in China, each basing on its own unique theory: MM and TCM, but arriving at some similar concepts, domains and facets.