Of the 63 patients who were diagnosed with CRPS in our clinic, 55 were enrolled in the study; 32 patients (58.2%) were male and 23 (41.8%) were female. The average age of the patients was 39.2 ± 15.0 (range 14-76) yr. Of the inciting events, 43 (78.2%) were trauma-related (e.g., following a fall, crushing injury, or contusion), 11 (20.0%) were surgery-related, and 1 (1.8%) had no obvious inciting event (spontaneous). In total, 51 patients (92.7%) were diagnosed with CRPS type I, while the remaining 4 (7.3%) were diagnosed with CRPS type II. Of all the patients in the study, 38 (69.1%) complained of pain in the lower limbs, 12 (21.8%) reported pain in the upper limbs, and 5 (9.1%) experienced pain in their upper and lower limbs. The right side was affected in 20 participants (36.3%), the left side was affected in 29 participants (52.7%), and both sides were affected in the remaining 6 participants (10.9%) (). The detailed localization sites recorded for each patient were as follows: 7 were in the right upper limbs (12.7%), 6 were in the left upper limbs (10.9%), 13 were in the right lower limbs (23.6%), 19 were in the left lower limbs (34.5%), 5 were in the right and left lower limbs (9.1%), 4 were in the left upper and lower limbs (7.3%), and 1 was in the left and right upper and lower limbs (1.8%).
Various characteristics of CRPS patients
Eleven patients (20.0%) retained their employment status, whereas 44 patients (80.0%) became unemployed. Of the patients who continued to work, 4 had maintained their work after the onset of CRPS and 7 had returned to work following a period of unemployment. Of note, 2 of the patients who had returned to work were employed by a different part of their company or had a new occupation, whereas 9 patients retained their position.
The mean duration from the diagnosis of CRPS to the time of the interview was 1,083.1 ± 743.4 (range, 252-3,710) days. The mean number of workdays lost owing to CRPS was 897.5 ± 796.5 (range, 0-3,640) days among all the patients, and the mean duration from the inciting event to unemployment was 25.5 ± 79.6 (range, 0-365) days. In 7 patients who returned to work after being unemployed, the average time taken for their employment status to change was 271.4 ± 212.9 (range, 30-660) days. The mean duration from the inciting event to the development of CRPS symptoms was 12.8 ± 21.9 (range, 0-60) days and from the developed symptoms to occur to a diagnosis of CRPS being confirmed, the mean duration was 406.7 ± 566.0 (range, 13-2,813) days. The demographical data, affected sites, and inciting factors were compared for the 2 groups (employed vs unemployed). There were no significant differences between genders, extremities, and inciting factors in both groups. Patients in whom the right side was affected were more likely to return to work (). However, after controlling for the period from onset to diagnosis (before or after 8 months) and the type of occupation of the patient, an affected right side was not an independent variable for maintaining employment ().
Fig. 1 Results of logistic regression analysis. Pain site was categorized by the side that was affected, either the left or right. The level of education of the patient was defined as follows: "equal to or less than high-school graduate" or "higher than high-school (more ...)
No significant differences were observed in the weight and height of the patients or the number of days from the diagnosis of CRPS to the time of the interview between the 2 groups. The number of daily working hours before CRPS onset was similar between the 2 groups; however, the number of days per week spent working before CRPS onset was lower in the employment group compared with the unemployment group (5.2 ± 0.5 vs 5.9 ± 1.2; P = 0.009). The mean age of the patients was significantly lower in the employment group (29.1 ± 16.8 vs 40.1 ± 12.6 yr; P = 0.021). Although pain score did not vary significantly between the 2 groups at the time of disease onset, it was relatively higher at time of interview in the unemployment group (4.5 ± 2.9 vs 7.0 ± 2.0; P = 0.002) ().
Various characteristics of CRPS patients
Patients who were diagnosed within 8 months (240 days) were more likely to be employed than patients diagnosed after 8 months (P = 0.014). In addition, patients with white-collar jobs were more likely to be employed than those with blue-collar jobs (P = 0.000). In this study, professions that were classified as white-collar jobs included teachers, clerical workers, financial managers, and students, whereas blue-collar jobs included manual-labor workers such as construction workers, restaurant workers, delivery men, drivers, carpenters, farmers, and housekeepers. Patients who had achieved a higher level of education also had a higher rate of employment (P = 0.006). However, the rates of employment were not related to the types of health insurance of the patients (). Finally, there were no significant differences observed in the positive signs of CRPS between the 2 groups ().
Duration of diagnosis, insurance, level of education, occupational characteristics of CRPS patients
Signs at time of first visit of CRPS patients
The logistic regression analysis showed that patients had achieved a higher level of education, had a white-collar job, and were diagnosed within 8 months were more likely to be employed ().