Knee osteoarthritis (KOA) is one of the most prevalent degenerative musculoskeletal conditions that affects many people worldwide [1,2]. KOA is characterized by the progressive deterioration of the articular cartilage within the knee joint, resulting in pain, stiffness, and impaired mobility [3]. The symptoms of KOA typically involve joint pain, swelling, and crepitus [4]. The causes of this condition involve a complex interplay of genetic predisposition, ageing, joint overuse, obesity, and mechanical stress, making them a significant and prevalent public health concern [5].

The epidemiology of KOA is of global concern. KOA is a leading cause of disability worldwide, affecting >250 million individuals [6,7]. In the United States, KOA ranks among the most common musculoskeletal disorders, with a prevalence of about 14,000,000 adults [8]. In Africa, the prevalence of KOA is increasing, mirroring the global trend, as urbanization and lifestyle changes contribute to increased joint stress.

The prevalence in Nigeria, though well-documented, is still a growing concern given the ageing population and shifting demographics. The prevalence of KOA has been reported in different populations. As of 2019, the global cases of the KOA were approximately 364.6 million with an estimated annual increase rate of 0.3% for both types [9]. A recent systematic review reported the pooled global prevalence of KOA in individuals aged ≥40 years as 22.9% [8], while 19.6–20.6% was reported by studies conducted among Nigerians of the same age range [10]. Although the overall prevalence of OA in Nigeria is lower than the global average, the estimated increase in cases from 1999 to 2019 was between 100 and 150% [9]. According to Akinpelu [11], the prevalence of KOA was 21.4% in females and 17.5% in males, resulting in a 1.2:1 sex skew. Age was positively and significantly (P: 0.001) correlated with the prevalence of KOA. Most respondents (98.5%) had moderate-extremely severe disease, and 90.2% of participants reported that KOA affected their performance.

Pain is a central feature in KOA, significantly impacting the quality of life of affected individuals. In KOA, the pain is often described as a deep, aching discomfort exacerbated by movement [12]. According to the Centers for Disease Control and Prevention [13], it is most pronounced during weight-bearing activities, such as walking or standing. Understanding the unique pain characteristics in these conditions is vital for effective diagnosis, treatment, and management, thereby improving the patient’s quality of life.

The diminished quality of life in individuals with KOA is a well-documented concern [4,13,14]. The chronic nature of this condition often results in physical limitations, reduced social engagement, and increased psychological distress. Activities of daily living become challenging, and sleep disturbances are common owing to pain [15]. Furthermore, persistent pain and functional limitations can lead to depression, anxiety, and decreased overall well-being [16]. Therefore, assessing the quality of life in patients with KOA is crucial for developing comprehensive care strategies.

The relationship between pain severity and quality of life in patients with KOA remains a topic of significant interest. While it is evident that chronic pain impacts an individual's well-being, there is a gap in the literature regarding the specific interplay between pain severity and quality of life. This study aimed to investigate the relationship between pain severity and quality of life of patients with KOA in healthcare facilities.

Material and methods: This was a cross-sectional study. A sample size of 82 was estimated using G power version 3. 1. 9. 7. The consecutive sampling method was used to recruit participants. The numerical pain rating scale was used to measure the pain experienced by the participants. Data on the participants’ quality of life were collected using the short form-36 questionnaire. Data were analysed using descriptive and inferential statistics.

Socio-Demographic Profiles of the Participants

Eighty-five individuals with KOA (52.9% female; mean age = 58.07 ± 13.43 years) participated in this study. The mean body mass index (BMI) (29.89 ± 6.12 kg/m²) of the participants fell within the range for being overweight, with most participants (78.8%) either not being physically active or being mildly physically active. Most participants were married (78.8%) and attained at least secondary-level education (63.5%) (Table 1).

Pain Severity and Quality of Life of Individuals with KOA

The participants experienced moderate pain severity with a mean score of 6.29 ± 1.79. Their overall quality of life scores, including all domains except for physical health and emotional problems, were above the 60^th percentile with a mean total score of 65.22 ± 18.55. The participants scored highest in emotional well-being and lowest in the role due to physical health (Table 2).

Table 1: Socio-demographic profiles of individuals with knee osteoarthritis.

Table 2: Pain severity and quality of life of individuals with knee osteoarthritis.

Correlation between Selected Socio-Demographic Profiles, Quality Of Life, and Pain Severity among Individuals with KOA Using the Spearman Rank Order Correlation

The participants’ pain severity had a significant and inverse correlation with their total quality of life (rho = 0.671, p < 0.001), indicating that individuals with higher pain severity reported lower total quality of life. No significant correlation was observed between any of the participants’ age, BMI, educational attainment, and physical activity with any of their pain severity and quality of life (p > 0.05) (Table 3).

Table 3: Spearman Rank Order Correlation showing the relationship between selected socio-demographic profiles, quality of life, and pain severity.

Mann–Whitney U and Kruskal–Wallis Tests Assessing Differences in Pain Severity and Quality Of Life across Sexes and Marital Status

No significant sex difference was observed in any of the participants’ pain severity (U = 887.00, p = 0.906) and quality of life (U = 844.50, p = 0.625) (Table 4). Moreover, no significant differences were observed in pain severity and quality of life across different marital status categories of the participants (p > 0.05) (Table 5).

Table 4: Pain severity and quality of life of individuals with knee osteoarthritis.

Table 5: Spearman Rank Order Correlation showing the relationship between selected socio-demographic profiles, quality of life, and pain severity among individuals with knee osteoarthritis.

This study aimed to determine the severity of pain and QoL and their relationship among people with KOA in selected health facilities in Anambra State.

The mean pain severity of the participants was moderate (6.29±1.79), and the QoL assessment mean score was 65.22±18.55. Participants’ pain severity had a significant and inverse correlation with their total quality of life (rho=-0.671, p<0.001). Our findings indicated a moderate mean pain severity level (6.29±1.79) among participants with KOA in Anambra State. This aligns with existing literature that underscores the pervasive nature of pain in individuals with KOA, contributing significantly to the impairment in their activities of daily living and overall well-being [22]. The reported moderate pain severity level is consistent with the progressive nature of OA, where pain is a common symptom that worsens over time [23]. However, participants with KOA report high pain levels [24]. These diversities in outcome could be attributed to the stage of OA and available treatment for participants in the two studies.

Pain and other symptoms of KOA may have a profound effect on QoL affecting physical function and other parameters [22]. Several risk factors are associated with KOA, including high BMI, advancing age, low physical activity level, and females. KOA is more prevalent in females, and they are at a higher risk of having KOA (52.9% were females, and 47.1% were males). This is similar to the findings of a cross-sectional survey conducted in Nigeria [11], where the prevalence of KOA in their study was higher among females than males. In addition, a study reported a higher proportionality of females with KOA [25]. Females have more body weight and less height than males, predisposing them to a higher possibility of being overweight or obese, which increases the potential for developing KOA. Women in developing nations are generally less active than their males, increasing the potential for KOA.

The observed mean BMI of 29.89±6.12 kg/m² among participants was within the overweight category, aligning with existing literature that highlights the high prevalence of obesity among people with KOA. Increased BMI is a significant risk factor for the development and progression of KOA [26-28]. The excess body weight places an additional burden on the knee joints, contributing to the degeneration of articular cartilage and the overall worsening of OA symptoms.

In this study, 78.8% of participants were either not physically active or only mildly physically active, supporting the low active level among people with KOA as reported by previous authors. Most patients had low physical activity levels, which was associated with the severity of the symptoms of the KOA [29]. Even though the mechanism between KOA and physical activities is unclear, physical activities plays a significant role in muscles strengthening, flexibility, and resilience, preventing injury and alleviating symptoms, such as pain and stiffness. No significant association was observed between the incidence of KOA and recreational physical activity. This can however be explained by the fact that not all recreational physical activities engage the lower limbs effectively, and for physical activity to directly impact KOA, activities that strengthen the muscles of the knee should be included in physical activities.

A significant inverse correlation was observed between participants' pain severity and their total QoL (rho=-0.671, p<0.001). Pain is a predominant symptom in KOA, and literature has consistently highlighted the detrimental impact of pain on the QoL among individuals with KOA [31-34]. Therefore, functional limitations, decreased mobility, and psychological distress contribute to a lower overall quality of life for individuals with KOA [35]. Furthermore, the mean total quality of life score (65.22±18.55) and scores in all domains, except the role owing to physical health (53.24±42.57) and emotional problems (59.22±45.54), crossing the 60th percentile suggest a generally fair quality of life among participants. The lower scores in the role owing to physical health domain are similar to previous studies highlighting the impact of KOA on functional limitations and the ability to perform daily activities [20,36]. These findings emphasize the multifaceted effects of KOA beyond pain, encompassing physical and emotional dimensions. Pain is not only associated with potential or actual tissue damage but a variable with emotional component always interpreted at the level of insula. [37,38] In a study, participants reported poor QoL in the physical functioning, psychological, social relationship, and environmental health domains [26]. Their study had additional information on presence of co-morbidities, such as obesity, hypertension, and diabetes, which were not observed among our study participants.

Contrastingly, no significant correlation was observed between participants' age, BMI, educational attainment, and physical activity with either pain severity or QoL. These results may contradict some existing literature that associates certain factors, such as BMI and physical activity, with the progression and management of KOA. Literature has consistently highlighted the impact of obesity on the development and exacerbation of KOA symptoms owing to increased mechanical stress on the joints [28]. However, the lack of correlation in this study could be attributed to the specific characteristics of the sample population or other unexplored variables that influence these relationships. Similarly, the absence of a significant correlation between age, educational attainment, and pain severity or quality of life contradicts some studies that suggest age-related differences in the experience and management of KOA [39]. The discrepancy may be influenced by the complexity of factors contributing to pain severity and quality of life in KOA, including individual variations, cultural factors, and socio-economic factors.

Our findings revealed no significant sex differences in either pain severity (U=887.00, p=0.906) or quality of life (U=844.50, p=0.625) among individuals with KOA in Anambra State. This outcome is consistent with some literature that suggests sex may not be a significant predictor of pain severity or quality of life in patients with KOA. While some studies have reported sex-specific variations in the prevalence, pain severity, and QoL in patients with KOA [34,40,41], others found no substantial sex disparities in pain experience or quality of life [42]. The absence of a significant sex difference in this study supports the latter perspective, emphasizing the need to consider individual variations in the experience of KOA.

Additionally, no significant differences were observed in pain severity and quality of life across different marital status. This is similar to some literature suggesting that marital status may not be a consistent predictor of pain severity or quality of life in individuals with chronic conditions, including KOA [43]. While marital status can influence social support networks and coping mechanisms, its impact on the specific aspects of KOA may vary among individuals. The absence of significant sex and marital status in pain severity and quality of life in this study may be influenced by various factors, such as cultural context, socio-economic conditions, and individual coping strategies.

Finally, this study's findings highlight the significant interplay between pain severity and quality of life among individuals with KOA in Anambra State. The strong inverse correlation emphasizes the need for targeted interventions to alleviate pain, with potential implications for improving the overall well-being of affected individuals. Additionally, the observed lack of significant correlations with demographic factors, such as age, BMI, and education suggests that the experience of KOA is complex and multifaceted, requiring personalized approaches to care. Furthermore, the absence of sex and marital status in pain severity and QoL underscores the importance of recognizing individual variations and tailoring interventions to address the unique needs of each patient. These implications emphasize the necessity for comprehensive and individualized strategies in managing KOA to relieve pain and improve the QoL for affected individuals in Anambra State.

Pain severity was significantly associated with the quality of life of people living with KOA. No sex differences were observed in either pain severity or QoL among individuals with KOA. The observed total quality of life score and scores in all domains suggest a generally fair QoL among participants. No significant differences were observed in pain severity and QoL across different marital status of the participants.

Conflicts of Interest

The authors declare no conflict of interest.

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