In this study, the prevalence of osteoarthritis in the stroke group was significantly higher than in the non-stroke group: 21.7% and 12.5%, respectively. In the stroke group, the prevalence of osteoarthritis increased with age up to 70–79 years, and was higher in females. This finding suggests that stroke survivors, especially those of older age and females, are more vulnerable to osteoarthritis than the general population.
Given Korea's progression to a super-aged society, the significance of stroke and osteoarthritis in Korea is expected to grow in the future. Additionally, due to advances in medical technology, the improved quality of health care, and health promotion over the past several decades, the mortality rate of acute stroke has decreased, and the survival period has increased. Considering what we continued to look at in this study, the longer the period of suffering from stroke, the more likely the degree of osteoarthritis symptoms in the patient group will affect HRQoL.
Stroke is a disease that is highly associated with chronic or permanent disorders. In particular, osteoarthritis may be accelerated due to biomechanical problems such as paralysis, spasticity, sensory loss, movement disorders, and physical disorders [23, 24]. Knee osteoarthritis in patients with stroke was associated with an increase in the length of hospitalization and was found to be related to the degree of their daily activities . Gait issues in patients with stroke showed a significant relationship with knee pain at rest, and knee osteoarthritis is known to be closely related to functional recovery after the onset of stroke [26, 27]. Therefore, when proper evaluation and management including rehabilitation for patients with osteoarthritis are provided, it could improve their HRQoL.
Second, the present study found that EQ-5D index scores in stroke patients with osteoarthritis were significantly higher in terms of mobility and pain/discomfort compared to the control group without osteoarthritis. The current findings indicated that hallmark symptoms (e.g., joint pain and gait difficulty) of osteoarthritis contribute to functional limitation and worsen HRQoL in the stroke group, suggesting that a preventive approach for stroke patients with osteoarthritis can improve their quality of life.
Lastly, HRQoL in the stroke group was affected by the presence of osteoarthritis, aerobic exercise, alcohol use, insurance type, and education level. Osteoarthritis and type of insurance (i.e., medical benefit) were associated with decreased HRQoL in the stroke group. That is, improving the medical benefit group’s financial situation can contribute to a better quality of life. The other factors associated with a positive effect on HRQoL were aerobic exercise and alcohol intake per week. These findings are consistent with previous studies reporting that aerobic exercise improves HRQoL in stroke patients  and highlights the role of patient education on physical activity and exercise. Interestingly, although HRQoL was higher in the alcohol intake group than in the no drinking group, caution is needed when interpreting this result. Further studies should be considered to investigate the effect of drinking habits and types of alcohol on HRQoL in stroke patients.
This study has several limitations. First, this was a retrospective cross-sectional study that included a survey; it is difficult to identify the sequential or causal relationships of stroke patients and HRQoL. Second, although we conducted a secondary analysis of the KNHANES, the number of samples used in the final analysis was 416, which is less than the total number of stroke patients in Korea. Third, the classifications and analyses according to detailed lesions, morbidity, or severity of osteoarthritis were not performed in detail. Future research is needed to analyze the relationship between the characteristics of osteoarthritis and HRQoL in stroke patients.