This was a cross-sectional, quantitative, observational study conducted from January 2023 to July 2023 at the Greys Hospital Tertiary Pain Clinic in Pietermaritzburg, KwaZulu-Natal, South Africa. The clinic serves a large, diverse population from urban, peri-urban, and rural areas, with the majority of patients being referred from primary or district-level facilities within the public health system. The multidisciplinary team includes anaesthesiologists, psychiatrists, psychologists, physiotherapists, occupational therapists, pharmacists, nurses, and social workers. The study sample comprised adult clinic attendees presenting for assessment or follow-up, predominantly black South Africans with varied educational backgrounds and a high prevalence of comorbid physical and mental health conditions, broadly representative of the provincial chronic pain population.

Consecutive adult patients attending their routine follow-up appointments at the Greys Hospital Tertiary Pain Clinic (Wednesdays and Fridays) between January 2023 and July 2023 were invited to participate. Consecutive sampling was used to minimise selection bias and enhance the representativeness of the clinical population. Patients are typically referred from district hospitals and community health centres across KwaZulu-Natal for multidisciplinary pain management. Inclusion criteria were: age 18–65, a confirmed diagnosis of chronic pain (≥ 3 months), completion of initial rehabilitation, proficiency in English (reading, writing, and speaking), and a minimum of Grade 7 education. Exclusion criteria included known neurological disorders, active psychosis, or significant communication impairments. Over the study period, 121 consecutive patients were seen; of these, 105 met eligibility criteria and were enrolled. The population was demographically mixed, predominantly black South African, with musculoskeletal pain, post-traumatic pain, and mixed neuropathic syndromes being the most common diagnoses. Study information sheets and flyers were distributed in the clinic waiting area.

Sample size estimation was based on a 20% prevalence of cognitive impairment reported by Landro et al.²¹ In the cohort of patients experiencing chronic pain, a sample size of 110 participants was required to achieve a 95% confidence interval with a margin of error of 7.5%, considering a 10% non-response rate; the final sample size to be achieved was 121 participants.

The principal investigator collected all data. A clinical data sheet was used to document the socio-demographic details, lifestyle factors, and clinical history. This clinical data sheet was derived from the research conducted by Narsi et al.²² All data were collected during a single clinic visit, taking approximately 25–30 min to administer. Each participant was first assessed with the Mini-Mental State Examination (MMSE), then the Montreal Cognitive Assessment (MoCA). The tests were administered and scored as instructed by the relevant instrument.

The data were systematically documented within a password-protected REDCap mobile database. Statistical analysis was conducted utilising Stata version 17, wherein Chi-Square tests or Fisher’s exact tests were employed for categorical variables, and t-tests or Mann-Whitney U tests were applied for continuous variables, contingent upon the data distribution. The normality of continuous data was assessed using the Shapiro-Wilk test, with the data presented as means alongside standard deviations (for normally distributed variables) or medians accompanied by interquartile ranges (for non-normally distributed variables). Categorical data were summarised as frequencies and percentages. To mitigate the impact of potential confounding variables, a multivariate analysis was performed, adjusting for pertinent socio-demographic and clinical factors. Associations between cognitive performance and independent variables, such as education level and cognitive impairment, were analysed using logistic regression models, establishing statistical significance at p < 0.05.

Approval for the access of medical records was acquired from the KwaZulu-Natal (KZN) Department of Health and the ethics committee of Greys Hospital prior to the initiation of data collection. Ethical clearance to conduct the study was granted by the Biomedical Research Ethics Committee of the University of KZN (reference number BREC/00004986/2022).

The analysis revealed no significant correlation between the presence of neurocognitive impairment, as assessed, and age. However, the male gender, evaluated through the MMSE, exhibited clinical significance (p = 0.03). In addition, individuals of African descent, evaluated by the MoCA were also found to be clinically significant (p = 0.001). The primary language spoken at participants’ residences did not demonstrate any clinical significance. Furthermore, individuals with no tertiary education showed a significant association with neurocognitive impairment, as indicated by both MMSE (p = 0.04) and MoCA (p = 0.02). The employment status of participants had no effect on the results of the assessments administered.

The clinical characteristic data presented in Table 2 indicate that 18% (n = 19) of the participants experienced a comorbid mental health condition, whereas 89.5% (n = 94) reported the presence of at least one medical comorbidity. None of the participants reported a history of head trauma or alcohol abuse; however, a significant 68.6% (n = 72) indicated a lifetime history of substance use. Importantly, back pain was identified as the most frequently reported type of chronic pain, with 93 individuals (88.6%) acknowledging its presence.

The clinical characteristics of participants with chronic pain showed no significant associations with any known mental illness diagnosis, medical comorbidity, or lifetime use of any substance. However, the MoCA alone did indicate that the presence of mental illness is significant with p < 0.05.

The prevalence of neurocognitive impairment among the evaluated participants was determined to be 55.2% (n = 58) based on the MMSE, and 73.3% (n = 77) as indicated by the MoCA. The statistical results are graphically presented in Figure 1.

The box and whisker plot for MMSE scores shows a minimum score of 13 and a maximum score of 27, with an interquartile range (IQR) from 21 to 25 and a median of 23. For MoCA scores, the plot indicates a minimum score of 14 and a maximum score of 30, with an IQR from 20 to 26 and a median score of 24.

Participants who presented with medical comorbidities and a history of lifetime substance use did not demonstrate any statistically significant findings. The use of the MoCA indicated a significant correlation with the presence of a mental illness (p = 0.005). In conclusion, the type of pain was not significantly associated with any impairment in neurocognition. Figure 2 illustrates the type of pain syndrome and the number of participants affected.

The bar graph shows back pain as the most prevalent pain syndrome, reported by 93 of 105 participants, with many experiencing multiple co-occurring pain syndromes; ‘Other’ includes conditions like Complex Regional Pain Syndrome (CRPS), hand and/or shoulder pain, post-operative pain, and others.

The study’s strengths include its prospective design and use of validated MMSE and MoCA for comprehensive neurocognitive evaluation. The MoCA enhances the reliability of the findings because of its heightened sensitivity in detecting mild dysfunction. The diverse sample of age, gender, and ethnicity enhances the generalisability of the results to similar clinical populations. Focusing on chronic pain patients, the study highlights the often-overlooked cognitive function, offering insights for future screening and interventions. The study considered socio-demographic and clinical factors, including education, employment, mental health, and substance use, for a holistic understanding.

Several limitations of this study are evident, particularly its cross-sectional design, which captures data at a singular point in time. This characteristic restricts the ability to establish causality between chronic pain, neurocognitive impairment, and associated factors. Recruiting from a single pain clinic may introduce selection bias, limiting generalisability and reflecting enhanced health-seeking behaviours. The study analysed cognitive function factors, but did not fully account for confounders such as medication use, pain severity, and socioeconomic status. Excluding non-native speakers because of language barriers may limit the representativeness of findings, particularly in multilingual populations. Reliance on self-reported data for substance use and comorbidities raises concerns about recall bias and underreporting. Although a correlation between neurocognitive impairment and a lack of tertiary education was found, cognitive reserve and lifelong learning were not explored.

Despite methodological limitations, this study provides valuable insights into the prevalence and associations of neurocognitive impairment in chronic pain patients. Future research with longitudinal designs and diverse samples could strengthen these findings and guide interventions to reduce cognitive decline. This study highlights the need for routine cognitive screening in chronic pain management, especially for high-risk groups such as males, Africans, and those with lower education levels.

Clinicians are encouraged to adopt a multidisciplinary methodology that integrates cognitive rehabilitation and mental health support alongside pain treatment protocols. Policy initiatives should focus on expanding education-based cognitive resilience programmes and ensuring integrated mental health and pain management services. Furthermore, efforts should be made to enhance the inclusivity of cognitive assessments by addressing language barriers. Future research should explore the causal relationship between chronic pain and cognitive impairment, considering pain severity, medication, and cognitive reserve.

Exploring the intersectionality of socio-demographic factors could yield deeper insights into cognitive outcomes among chronic pain populations. These findings highlight the importance of a holistic pain management approach, addressing cognitive, psychological, and social factors to improve outcomes.