Towards patient-centred cancer care: cross-cultural validity and responsiveness of the Turkish Integrated Palliative care Outcome Scale

A comparative review of palliative care development in the Middle Eastern Cancer Consortium (MECC) member countries identified ‘lack of awareness and understanding of palliative care needs at public, government and professional levels’ as barriers to provision of palliative care to cancer patients in this region [1]. These observations maintain their relevance today for cancer patients living in MECC member countries including the setting for this study, Cyprus. Palliative care as ‘ … an approach that improves the quality of life of patients and their families … through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems, physical, psychosocial and spiritual’ [2] is rarely recognized [3]. As a concept, palliative care is only equated with management of pain in cancer and available only in oncology inpatient and intensive care units [4].

Within Cyprus, resources for health services including community home-based services are scarce and receive no or little government support. The health expenditure is the lowest compared to other European Union member countries and 25% of the population has no access to public health services [5]. Early palliative care as cost-effective intervention in cancer patients has already been demonstrated [6]. Evidence of the effectiveness and cost-effectiveness of palliative care services may promote their integration for persons living with all serious illnesses in Cyprus. After years of lobbying, local cancer charities have been formally authorized to deliver community home-based palliative care services in Cyprus [4, 7]. This recognition may serve as a ‘catalytic action’ [8] that may increase the coverage of the palliative care services beyond inpatient and intensive care unit settings to the community. The charities must support home services through fundraising and ensure their resources address the most important concerns early. This has necessitated availability of a brief and valid patient-reported outcome measure (PROM) to describe the most important concerns of people with living with cancer.

Routine use of PROMs can improve the quality and relevance of services [9] and also can help build awareness in healthcare providers about the most important needs of patients and families [10]. The Integrated Palliative care Outcome Scale (IPOS) is a valid brief PROM that addresses the most important concerns such as symptoms, information needs, practical concerns, anxiety and low mood, family anxieties and overall feelings of being at peace of persons living with serious illnesses, such as cancer [11, 12]. IPOS has been used with cancer patients [13, 14] and adapted to many cultures [15‐17].

In this study, we first translated and culturally adapted IPOS into Turkish, and evaluated the cross-cultural validity and responsiveness of IPOS in Turkish speaking community of cancer patients in Cyprus. The findings of the study could have implications for millions of patients living with serious illnesses around the world who have Turkish as their native language [18].

The study commenced after attaining permissions from the POS Development Team as the copyright holder of IPOS, the EuroQol Group for use of Turkish version of EQ-5D-3L. Ethical approval was obtained from the Eastern Mediterranean University Publication and Research Ethics Committee (ETK00–2017-103). Written informed consent was obtained from all participants included in the study.

Literature and consultations confirmed that IPOS covered all of the relevant concepts in relation needs and concerns and had face and content validity. Pain and emotional difficulties emerged as the most prevalent issues. In the 2 forward translations there were differences in the grammatical tense used; translators used present continuous tense, but the mediators used past tense. The item on practical problems resulting from illness was particularly challenging, therefore the word ‘practical’ was removed and the question revised to ask about ‘personal and financial problems’ caused by illness. The 2 blind backward translations produced from final reconciled forward translation of Turkish IPOS were both similar with no significant differences in meaning. The expert panel reviewed all versions to improve clarity and produced the pre-final Turkish IPOS.

Following cognitive testing, instructions were reworded and further shortened. The response options were generally clear and well understood; the only difficulty was with ‘occasionally’ which was suggested to be changed to ‘zaman zaman’ rather than ‘ara sıra’. Patients struggled with the information item which was revised to emphasize that the question was not about the knowledge the patients possessed but the information given to them. Turkish IPOS Pre-approval Version was sent to the Cicely Saunders Institute POS Team for independent review. Following this and minor amendments, Turkish IPOS was produced and validation study was initiated.

For the validation study, data collection took place between July 2017 and October 2018. Participants were mostly women (73.5%), almost all were struggling with treatment expenses (91.5%) and most received support from family members (83.3%). Of the 43.6% who reported having comorbidities, 50% had hypertension and 28.4% had diabetes (Table 1). Fifty three percent of the participants had advanced cancer and breast cancer was the most prevalent (48.3%).

MVA identified four items with higher number of missing responses in baseline assessment (9.4–7.7%) (Table 2). As the data were not missing completely at random (Little’s MCAR test χ² = 291.512, DF = 184, p < 0.0001), listwise deletion or imputation of missing values was not undertaken. Patients at moderate stages of their illness (Stage II and III) had more than 5% of responses missing for these items. Only two items were missing 1 response each in the follow-up assessment.

CFA fit indices were CFI = 0.756 and SRMR = 0.0002 indicated poor fit of the model to the data (χ² = 496.369, df = 87, χ²/df = 5.705, p < 0.0001) and post-hoc modifications were made. Post-hoc modification involved adding in covariances of error terms based on theoretical and relevant associations of items measured. The model fit improved where CFI = 0.855 and SMRM = 0.0002 (χ² = 321.874, df = 78, χ²/df = 4.127, p < 0.0001). Even though the CFI and SMRM parameters approached the minimums, they were not within the required defined parameters recommended for small samples. For this reason, the CFA was inconclusive and cross-cultural validity could not be confirmed or negated. The standardized parameter estimates of the modified model are shown in Fig. 1. Physical factor accounted for 73–21% of variance, Emotional factor for 25–11% and Social Impact and Quality of Care (Support) for 50–32% of the relevant IPOS items. Emotional subscale, had poorly loading items where Anxiety and Anxiety of Friend and Family had factor loadings of 0.32 and 0.35 respectively (see Table 3 and Fig. 2 for distribution of scores).

The Emotional sub-scale showed poor internal consistency (α = 0.64), three of the items were worthy of retention but deletion the item on anxiety of family and friends would increase α to 0.75. The reliability of this subscale was also poor (ICC = 0.31, 0.24–0.39, 95% CI). The Physical subscale showed good internal consistency (α = 0.91) but moderate reliability (ICC = 0.51, 0.45–0.56 95% CI). Social and Quality of Care Issues subscale showed good internal consistency (α = 0.75) and marginally moderate reliability (ICC = 0.50, 0.42–0.57 95% CI).

The participants listed feeling worried, financial difficulties, lack of support, impact of cancer on the family on activities of everyday life as their main concerns in response to the open-ended first question in IPOS. As these topics were all covered by IPOS, its content validity was reconfirmed.

Correlations with EQ-5D-3L domains were significant and, mostly in the directions and strength predicted (Table 4). For example, IPOS Emotional subscale, had low correlations with EQ-5D Mobility, Self-care, Usual Activity, slightly higher but still low correlations with Pain/Discomfort and Anxiety/Depression and moderate negative correlation with self-rated health.

Known-group validity was indicated as there was a significant difference in the total scores for early (M = 22.03, SD = 10.39) and advanced (M = 25.51, SD = 9.27) stages; t (128.526) = − 2.274, p = 0.025. Similarly, participants at earlier disease stage had significantly lower Social and Quality of Care sub-scores (M = 4.87, SD = 2.75) than participants at advanced stages of cancer (M = 6.41, SD = 2.25), t (123.635) = − 3.955, p < 0.0001. The Physical and Emotional sub-scale scores for participants at early and advanced stages were not significantly different.

The mean time between the two administrations were 4.6 weeks (Range = 2–7, SD = 1.5). SRM of − 0.94 suggests large responsiveness [33]. Total scores at follow-up were significantly lower compared to baseline with a mean difference of 9.87 (7.18–12.58, 95% CI), t (57) = 7.33, p < 0.0001. A similar trend was observed for the physical (x₁-x₂ = 7.02, t (72) =10.3, p < 0.0001) and quality of care/social support subscales (x₁-x₂ = 2.11, t (61) =6.35, p < 0.0001). However, emotional concerns significantly worsened compared to baseline (x₁-x₂ = − 1.74, t (61) = − 4.2, p < 0.0001). Figure 3 maps change scores for 58 cancer patients with complete data across all four scales and assessments (Fig. 3).

In this study we adapted IPOS to Turkish and evaluated its cross-cultural validity and responsiveness in cancer patients. Most of the items were translated easily and perceived to be culturally relevant. Contrary to experiences of teams working on other language translations [16, 34], “at peace” item was particularly easy to adapt to Turkish as this is a very culturally relevant concept. Items on “practical problems addressed” and “information” were the most challenging to translate and adapt because the word “practical” is commonly used interchangeably to refer to “application”, and “information” can translate to “knowledge possessed”. Both items were clarified during cognitive testing.

Studies with cancer patients may be missing data [35] and higher rates of responses may be missing in palliative care studies compared to other studies [36]. Data for the baseline and follow-up assessment were impressively complete for most of the items. The baseline assessment of items on depression, information, anxiety of friends and family, and sharing feelings with friends and family generated the most non-responses. It is possible that patients may be struggling to come to terms with their cancer diagnosis or struggling to express the emotional impact of cancer on themselves, friends and family [37, 38]. Also, participants may have felt uncomfortable expressing their true responses to the item on “information” as not to offend the community palliative care staff caring for them, as was observed in the Japanese IPOS validation study [14].

Evaluation of SRMR and CFI values of the final CFA model could not confirm or negate that the three-domain structure proposed in the original IPOS was an acceptable fit to our data [39], in the original validation study 2-factor solution was implicated to be better fitting [11]. Even though CFI and SMRM parameters approached the minimums, they were not within the required defined parameters recommended for small samples. Future larger studies may be needed to confirm the three-domain structure. Emotional subscale, specifically had poorly loading items. Lack of consensus on cut off criteria for factor loadings in studies with small samples [40], necessities future larger studies before further actions are taken in relation to removal of items.

Turkish IPOS is acceptable, with no floor or ceiling effects. The mean and standard distribution of scores are consistent with findings from a recent validation study in cancer patients [14]. Turkish IPOS illustrated moderate to marginally moderate internal consistency and good to moderate reliability with its Physical and Social and Quality of Care subscales. However, the Emotional sub-scale showed poor internal consistency and reliability. These results agree with the findings in the original validation study [11], which reported low internal consistencies for Emotional and Social and Quality of Care subscales. In line with observations from the CFA, the removal of the item ‘Have any of your family or friends been anxious or worried about you?’ is indicated for improving internal consistency.

Content and face validity, ascertained through the translation and cross-cultural adaptation phase as well as at the validation phase, was also good as all of the main concerns such as feeling worried about treatment, the future, loss of independence and dying, the impact of the illness on the family, financial impact of illness, issues with getting support and pain were the main concerns brought up in the open-ended questions were covered in IPOS.

Construct validity was demonstrated with significant but moderate to low correlations with EQ-5D-3L items and VAS scale in the predicted direction. These findings were consistent with the findings of the Japanese IPOS [14]. Turkish IPOS also demonstrated known-groups validity as cancer patients at advanced stages had significantly higher total IPOS scores.

Turkish IPOS was able to detect statistically significant changes in concerns and symptoms between baseline and follow-up assessments. The effect size statistics were large. These findings supported internal responsiveness of the Turkish IPOS. The improvement in the total score was mostly due to significant improvement in the physical and quality of care/social support aspects. However, small but significant deterioration was reported with the emotional subscale. The general improvement or deterioration in the scores could be the effect of home palliative care services, but further studies are required to understand these changes in the context of clinical and subjective meaning [41].

There are further limitations of this study which need to be acknowledged. Patients were recruited through convenience sampling and may not be representative of all cancer patients. Additionally, patients receiving community palliative care services from the cancer charity may be more financially disadvantaged compared to the overall population of cancer patients. Patients with breast cancer were over-represented in the study as the charity was established by a breast cancer survivor and attracts more memberships among women living with breast cancer. Also, more women participated in the study as men may be less willing to share their experiences of having cancer [42]. These limitations may affect the generalizability of the findings.

The potential regional differences in Turkish language must also be taken into consideration. For this reason, minor amendments might be needed before Turkish IPOS is used in other Turkish speaking communities.

A team of researchers in Turkey have recently completed the cognitive testing of Turkish IPOS and have confirmed initiation of validation work with no revisions or modifications. Further research is needed to establish the range of Turkish IPOS scores that indicate clinical change meaningful to the patient and to establish its reliability and validity in non-cancer patient populations.

Turkish IPOS is simple to complete and clearly understood. It measures the important aspects of needs and concerns that are relevant to Turkish speaking cancer patients and it is acceptable. Physical and Social and Quality of Care subscales are internally consistent and reliable, can be used to evaluate needs and concerns in these areas. There is good evidence that Turkish IPOS is a valid measure of concerns and needs, and responds to the severity of illness and is able to measure change over a specified time frame. Future studies are necessary to investigate the performance of the Emotional subscale, to clarify the factor structure and to evaluate the extent to which change in a IPOS relates to corresponding change in a reference measure of clinical or health status. Observing regional differences, Turkish IPOS may have implications for use in other Turkish speaking communities.