Usage of glaucoma-specific patient-reported outcome measures (PROMs) in the Singapore context: a qualitative scoping exercise

Important aim of quality health care is the patient-centeredness and a focus on patient experience [1]. However, healthcare professionals have traditionally defined “successful glaucoma treatment” based on objective clinical endpoints such as lowering of intraocular pressure (IOP) and slowing or stopping visual field deterioration [2]. These clinical measures may result in more disease-centric care as opposed to more patient-centric care which requires a more holistic view of care delivery, since they only surrogate measures of an effective treatment paradigm, and cannot fully capture the actual impact of glaucoma and its treatment on patients’ daily lives [3, 4], considering the chronic progressive nature of glaucoma and its potential to substantially and negatively affect patient’s daily functioning [5]. Furthermore, insights into how glaucoma affects patients’ lives might provide a means of tailoring treatment strategies to meet the individual’s specific need [5].

The increasing realization that clinical parameters alone are inadequate to assess health outcomes has resulted in the widespread use of patient-reported outcome measures (PROMs) [6]. PROMs are a series of standardised and validated questions self-reported by patients to assess their perspectives on the impact of diseases and treatment on their own health status, well-being and functioning [6‐8]. Especially disease-specific PROMs, as the gold standard for relevant endpoint measures of patients’ subjective experiences, are important to clinicians as feedback on the care they have provided and for assessing the quality of care provided by healthcare services. PROMs have been widely used as effectiveness endpoints for approved drug labels in the United States [7], and outcome assessment in clinical guideline development (e.g., for pain management [9], dialysis treatment [10], and screening for prostate cancer [11]), as well as applied in the context of national audits [12], clinical governance and quality assurance [13], and integrated into routine clinical practice [14] and managing the performance of healthcare providers [15].

However in glaucoma, most attempts to measure health improvement from treatment have largely been in clinical research studies on selected population and much less frequently in routine clinical practice [16, 17]. Also, there is a plethora of PROMs with considerable heterogeneity amongst them, such as differing in terms of how the answers are scored, as well as the number, nature and the wording of the questions asked. The quality of these PROMs instruments also varies considerably in terms of their validity and reliability [16, 18]. Moreover, although most of glaucoma-specific PROMs have been constructed in accordance to basic psychometric principles [19], a conceptual framework building on patient views is absent in more than 50% of instruments [16]. The ethos of PROMs is to gauge patients’ assessment on their own health status and health-associated quality of life. So arguably, the lack of patient input in the development process of these PROMs has been cited as a methodological shortcoming. An appropriate PROM should be supported by published evidence presenting that it is acceptable to patients, as well as valid, reliable, and responsive (sensitive to change) [20]. Additionally, feedback from healthcare professionals on PROMs use is also essential addition to any PROM development [21].

In Singapore, there has also been growing interest in exploring the use of PROMs in routine glaucoma care. However, most, if not all available PROMs have been developed in the context of largely western populations with different healthcare systems [16, 18]. Singapore, on the other hand, is a multi-ethnic country with a majority population of Chinese (74.2% of the resident population), with substantial Malay (13.2%), Indian minorities (9.2%) and other ethnicities (3.3%). Little is known on the use of these PROMs in a multi-ethnic Asian country like Singapore with a different healthcare system.

Hence, our study aimed to qualitatively gauge the relevance, comprehensiveness and acceptability of using four glaucoma-specific PROMs, namely: the Glaucoma Quality of Life-15 (GQL-15) [22], Glaucoma Symptom Identifier (GSI) [1], Independent Mobility Questionnaire (IMQ) [23], and Treatment Satisfaction Survey of Intra-ocular Pressure (TSS-IOP) [24], in the routine glaucoma care in the Singapore context. These four glaucoma-specific PROMs were selected based on a systematic review identifying them as the PROMs with the greatest potential for further adaptation and testing in the clinical setting [16]. To achieve our aim, we conducted a semi-structured interview with healthcare professionals and glaucoma patients about their perceptions on the content of one of four selected PROMs instrument and issues relating to the administration. A feasibility survey was performed upon the conclusion of the semi-structured interview.

This study was approved by the Institutional Review Board of Singapore National Healthcare Group.

“Exploratory pilot work to assess comprehensibility, acceptability, relevance and answerability to the target population” is one step of a systematic 5-step approach to valid PROMs [25]. In our study, this step is taken to see if selected 4 PROMs have the pre-requisites for use in routine glaucoma care, negating the need for more extensive development work to create a novel PROM. To our knowledge, this is the first exploratory study that assesses the healthcare professionals’ and glaucoma patients’ perception on the content and administration of glaucoma-specific PROMs in the Singapore clinical setting.

Our results demonstrate both positive and negative aspects of glaucoma-specific PROMs for their use in the daily clinical practice. Positive aspects include the majority of healthcare professionals and patients feel that selected PROMs are relevant to patients and healthcare team. Although patients with mild glaucoma did not see the relevance of PROMs in their care, citing: “for a mild glaucoma patient, this may not be relevant” (Table 2), it can be argued that the role of PROMs in the early stage of glaucoma may still have a role in terms of assessing the impact of treatment, such as side-effects and cost incurred from treatment.

The negative aspects in our study include barriers for glaucoma-specific PROMs in routine use. Several barriers (such as logistical, social, legal, technical, and cultural barriers) have been revealed to prevent the successful embed of PROMs into the routine clinical practice [14]. Several studies have shown the attempt to collect PRO data on a large scale in the routine eye clinic setting is disappointing [27, 28]. In our study, there are concerns expressed by the participants on the user-friendliness, comprehensiveness and logistics (Tables 2 and 4). For example, the need for brevity, and the instrument should not be too long. This has also been borne out by another study looking at the Impact of Vision Impairment questionnaire, which has the best domain coverage but is poor at assessing glaucoma patients, and may be too long for routine clinical use [27]. Our participants also feel it is impossible for patients with visual impairment to self-fill PROM questionnaire in the paper format (Table 2). Browne J et al.’s study also reflects the same concern to use VF14 to assess cataract surgery [27]. The howRu instrument is effective when conducted by telephone, which may solve the potential obstacles for the PROM questionnaire used by patients with visual impairment in routine practice [29]. It would be interesting to assess glaucoma patients’ views on howRu in Singapore clinical setting in future studies.

An assessment of 11 glaucoma-specific Health-related Quality of life (HRQoL) instruments concludes that little PRO instrument covers comprehensive domains which participants are interested in [30]. Our participants also expressed a desire for a more comprehensive PROM instrument that covered more holistic issues such as financial burden of care and psychological impact of disease (Table 2). For instance, “peace of mind” concerns between 50% [31] and 80% [32] of newly diagnosed glaucoma patients, but this item has been mentioned by little glaucoma-specific PROM instruments [27]. Participants in our study reflect the similar finding that selected PROMs did “not sufficiently address patient’s concerns, fears and doubts” (Table 2). The need for inclusion of the financial impact of disease is a finding that may be unique to Singapore where patients bear a significant direct out-of-pocket burden for their care [33]. This again illustrates the need for contextual relevance when using PROMs and caution in directly “importing” PROMs that have been developed for other healthcare settings.

Our study also reveals challenges in execution that may be unique to our local context. From the outset, recruitment of willing participants proved difficult. More specifically, our recruitment is biased toward the educated participants with 54% having tertiary education (Table 1). This may be a reflection of language constraints as English was used throughout the interviews and the PROMs were all worded in English. It is noteworthy that PROMs, as a meaningful clinical routine use, must also include good generalizability to ensure that sections of the patient population are not excluded – especially the less well-educated and well-off who also tend to be more severely impacted by disease. Additionally, in our study, it is noteworthy that we recruited no Malays (Table 1), which may again reflect poor participation in this racial group due to greater comfort in using Malay as a medium of communication. Our study shows that the use of PROMs in Singapore should be available in the four main languages here, namely: English, Chinese, Tamil and Malay.

The limitations of current study should be considered. The selected PROMs may be inadequate and more work needs to be done before a large scale PROMs program can be rolled out locally. This is especially so when applied to routine care as opposed to more research-oriented settings. For a PROM to be used in the daily practice, it is important to ensure that data collection is practical and equitable, and the data produced are valid as guidelines to improve patient care and prioritize healthcare resources. Looking at the socio-demographic data from our study, it is noted that the majority participants are male (79%), while female participants is 21% (Table 1). In terms of educational status, half of participants (54%) have received the tertiary level education. There is also no Malay participant in our study. The study numbers are small to begin with and the study design qualitative in nature. However, these findings may have implications for the wider usage of PROMs in routine care. It is well-known that socioeconomic status has close correlation with the health status of an individual. Socioeconomic factors may also similarly skew response rates and response patterns such that the poorer, less educated and sicker end up being under-represented or missed altogether. In Singapore, a significant proportion of the elderly do not know English –there may be a need to have a Chinese, Indian and Malay version of the same instrument to improve generalizability. More extensive studies need to be undertaken to explore this aspect and factored into the design, not only of the instruments themselves but the logistical aspects surrounding the application of these instruments to ensure representativeness.

Despite the above limitations, we have the strength in qualitative research method-think aloud method, which is commonly used during questionnaire development to determine whether the meaning of a questionnaire item, as interpreted by the questionnaire respondent, is consistent with the questionnaire developer’s intention of that item [25]. We employed this method to garner views from participants. This method has also been used to assess glaucoma patients’ perceptions on the acceptability, relevance, comprehensibility and answerability of one glaucoma-specific PRO instrument - the Aberdeen glaucoma questionnaire [25].

As the paradigm of what constitutes successful treatment shifts, PROMs will gain in prominence, and Singapore is no exception. It is heartening to know the use of glaucoma-specific PROMs is broadly welcomed by healthcare professionals and patients here. Also, our study highlights the need for caution in directly employing PROM instruments developed in other healthcare settings and the need to “contextualise” and frame these instruments for the local socio-demographic to ensure representativeness of the data collected. The identified barriers should be necessarily considered when designing and deployment of glaucoma-specific PROM instrument.