Development, validation and initial application of a patient-reported outcome measure to assess treatment burden for people living with multimorbidity in low-income settings in South Africa (SIMMBA)
Abstract
Background Treatment burden is a key determinant of outcomes for people living with multimorbidity (PLWMM). However, contextually appropriate measures are lacking in low-income settings. We developed and conducted initial validation of the SIMMBA patient-reported outcome measure (PROM) to assess multidimensional treatment burden in South Africa. Methods Following COSMIN guidelines, items were generated through literature review, expert consultation, and cognitive interviews, and translated into local languages, Afrikaans and IsiXhosa. A cross-sectional study was conducted among 332 adults with multimorbidity attending public primary care clinics in Cape Town. Psychometric evaluation included exploratory factor analysis (EFA), internal consistency (McDonald’s omega and Cronbach’s alpha), test–retest (n=99) reliability (Spearman correlation and intraclass correlation coefficients [ICC]), and differential item functioning (DIF) by gender. Results Internal consistency was acceptable to good across all domains (ω=0.54–0.83; α=0.643–0.803), except medication burden (ω≈0.21). Most domains showed no evidence of DIF, with two items flagged. Test–retest reliability was predominantly poor to fair (ICC range 0.33–0.55), indicating limited temporal stability. EFA supported a 64% of variance, with generally strong item loadings, although some cross-loadings and low communalities were observed. Participants reported highest burden in the financial domain and lowest in social support. Conclusions The SIMMBA PROM demonstrates promising preliminary validity in capturing context-specific treatment burden among PLWMM in low-income South African settings. However, further structural refinement, convergent validation, and improved reliability testing are required prior to implementation.
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BibTeX
@article{pinxteren2026development,
title = {{Development, validation and initial application of a patient-reported outcome measure to assess treatment burden for people living with multimorbidity in low-income settings in South Africa (SIMMBA)}},
author = {Myrna van Pinxteren and Charlotte Slome and Peter Delobelle and Lovemore Mapahla and Naomi S. Levitt},
journal = {Journal of Multimorbidity and Comorbidity},
year = {2026},
month = oct,
doi = {10.1177/26335565261493624},
url = {https://doi.org/10.1177/26335565261493624},
note = {CC BY},
}
RIS
TY - JOUR
TI - Development, validation and initial application of a patient-reported outcome measure to assess treatment burden for people living with multimorbidity in low-income settings in South Africa (SIMMBA)
AU - Myrna van Pinxteren
AU - Charlotte Slome
AU - Peter Delobelle
AU - Lovemore Mapahla
AU - Naomi S. Levitt
PY - 2026
DA - 2026/10/23
JO - Journal of Multimorbidity and Comorbidity
DO - 10.1177/26335565261493624
UR - https://doi.org/10.1177/26335565261493624
AB - Background Treatment burden is a key determinant of outcomes for people living with multimorbidity (PLWMM). However, contextually appropriate measures are lacking in low-income settings. We developed and conducted initial validation of the SIMMBA patient-reported outcome measure (PROM) to assess multidimensional treatment burden in South Africa. Methods Following COSMIN guidelines, items were generated through literature review, expert consultation, and cognitive interviews, and translated into local languages, Afrikaans and IsiXhosa. A cross-sectional study was conducted among 332 adults with multimorbidity attending public primary care clinics in Cape Town. Psychometric evaluation included exploratory factor analysis (EFA), internal consistency (McDonald’s omega and Cronbach’s alpha), test–retest (n=99) reliability (Spearman correlation and intraclass correlation coefficients [ICC]), and differential item functioning (DIF) by gender. Results Internal consistency was acceptable to good across all domains (ω=0.54–0.83; α=0.643–0.803), except medication burden (ω≈0.21). Most domains showed no evidence of DIF, with two items flagged. Test–retest reliability was predominantly poor to fair (ICC range 0.33–0.55), indicating limited temporal stability. EFA supported a 64% of variance, with generally strong item loadings, although some cross-loadings and low communalities were observed. Participants reported highest burden in the financial domain and lowest in social support. Conclusions The SIMMBA PROM demonstrates promising preliminary validity in capturing context-specific treatment burden among PLWMM in low-income South African settings. However, further structural refinement, convergent validation, and improved reliability testing are required prior to implementation.
SN - 2633-5565
ER -