Frequency of Radiologic Procedures in Patients With RA
Frequency of Radiologic Procedures in Patients With RA
The study population included 650 patients with RA and 650 subjects without RA. The mean age of the patients was 55.8 years, and 69% were female. A total of 27,088 radiologic procedures were performed among patients with RA and 21,006 among non-RA subjects, during a total of 7358 py of follow-up for the RA and 7597 py of follow-up for the non-RA subjects (rate ratio [RR], 1.32; 95% confidence interval [CI], 1.30–1.35). These radiologic procedures included conventional radiographs of the elbow, shoulder, wrist, hand, hip, knee, ankle, feet, chest, and spine, as well as computed tomography (CT) and magnetic resonance imaging (MRI) of the head and upper and lower extremities, radionuclide bone imaging, mammograms, and DXA scanning.
Patients with RA had significantly more conventional chest radiographs compared with those patients without RA (RR, 1.33; 95% CI, 1.28–1.38). This was also the case for upper extremity (RR, 2.97; 95% CI, 2.80–3.17), lower extremity (RR, 2.05; 95% CI, 1.94–2.16), bone radionuclide (RR, 1.90; 95% CI, 1.50–2.44), and DXA imaging (RR, 1.77; 95% CI, 1.59–1.98).
Patients with RA also had significantly more conventional radiographs of the spine (RR, 1.46; 95% CI, 1.35–1.59), hip, pelvis, and sacroiliac joints (RR, 1.14; 95% CI, 1.03–1.26) (Table 1). Among patients with RA, having a positive rheumatoid factor (RF) was associated with an increased likelihood of undergoing radiologic procedures (RR, 1.05; 95% CI, 1.02, 1.07).
Similarly, among the RA patients, women underwent more imaging procedures than did men (RR, 1.20; 95% CI, 1.16–1.23). This was also true, and the results were nearly identical for patients without RA (RR, 1.20; 95% CI, 1.17–1.24). Among patients without RA, the use of radiologic procedures overall has increased somewhat in recent years (RR, 1.08; 95% CI, 1.05–1.12 for subjects with index date in 1998–2007 compared with 1988–1997), most likely due to increases in the use of advanced imaging (CT, MRI). However, among patients with RA, we did not find a significant change in the rate of radiologic procedures overall among patients with RA diagnosed in 1998 to 2007 compared with those diagnosed in 1988 to 1997 (RR, 0.98; 95% CI, 0.96–1.01).
Computed tomography/MRI of the upper and lower extremities increased in patients with RA diagnosed in 1998 to 2007 compared with those diagnosed in 1988 to 1997 (RR for upper extremity, 4.53; 95% CI, 2.69–8.62; RR for lower extremity, 2.22; 95% CI, 1.57–3.25). Whereas CT/MRI of upper and lower extremities also increased for subjects without RA whose index date was in 1998 to 2007 compared with those with index date in 1988 to 1997 (RR for upper extremity, 2.99; 95% CI, 1.70, 5.96; RR for lower extremity, 3.09; 95% CI, 1.91, 5.47), the rate of CT/MRI of upper and lower extremities among patients with RA was significantly increased compared with those without RA during the entire study period (RR for upper extremity, 1.66; 95% CI, 1.27–2.19; RR for lower extremity, 1.76; 95% CI, 1.41–2.20).
Hand/wrist radiographs were obtained in 57% of patients within 1 year after initial RA diagnosis, but during the 1 to 3 years after diagnosis, only 42% had undergone hand radiographs, and only 32% had hand radiographs during 3 to 5 years after the diagnosis. Beyond 5 years of the initial diagnosis, the percentage of patients with RA who had routine hand radiographs every 2 years plateaud around 28%. A subgroup analysis demonstrated that the cumulative incidence of patients with hand/wrist radiographs within 1 year after RA diagnosis was significantly higher in patients who were RF (62%) than in those with negative RF (45%; P < 0.001). This difference persisted during 1 to 3 years after RA diagnosis (46% in RF vs 34% in RF; P = 0.003), 3 to 5 years after RA diagnosis (37% in RF vs 23% in RF; P < 0.001), and 5 to 7 years after RA diagnosis and (34% in RF vs 25% in RF; P = 0.046). The cumulative incidence of radiologic procedures was no longer significant at 7 to 9 years after RA diagnosis (30% in RF vs 23% in RF; P = 0.15) or beyond (28% in RF vs 26% in RF at 9–11 years after RA diagnosis; P = 0.62) (Figure).
(Enlarge Image)
Figure.
Percentage of patients with RA who had at least 1 hand/wrist radiograph in a 2-year period according to years since RA diagnosis by RF positivity (circles = RF negative, squares = RF positive). Asterisks under the x axis indicate statistically significant differences between groups (P < 0.05).
Female patients with RA had more radiologic procedures than their male counterparts (RR, 1.20; 95% CI, 1.16–1.23). Similarly, DXA scans were more frequently obtained in women than in men (RR, 2.25; 95% CI, 1.89–2.71). Mammography was performed only in female patients and was less frequently obtained in women with RA than in women without RA (RR, 0.93; 95% CI, 0.88–0.99).
To account for the increased number of diagnostic modalities in the last decade, we conducted a subgroup analysis comparing the periods of 1988–1997 and 1998–2007 and found no significant difference in the number of radiologic studies between these time periods among patients with RA (RR: 0.98, 95%; CI: 0.96–1.01).
Results
The study population included 650 patients with RA and 650 subjects without RA. The mean age of the patients was 55.8 years, and 69% were female. A total of 27,088 radiologic procedures were performed among patients with RA and 21,006 among non-RA subjects, during a total of 7358 py of follow-up for the RA and 7597 py of follow-up for the non-RA subjects (rate ratio [RR], 1.32; 95% confidence interval [CI], 1.30–1.35). These radiologic procedures included conventional radiographs of the elbow, shoulder, wrist, hand, hip, knee, ankle, feet, chest, and spine, as well as computed tomography (CT) and magnetic resonance imaging (MRI) of the head and upper and lower extremities, radionuclide bone imaging, mammograms, and DXA scanning.
Patients with RA had significantly more conventional chest radiographs compared with those patients without RA (RR, 1.33; 95% CI, 1.28–1.38). This was also the case for upper extremity (RR, 2.97; 95% CI, 2.80–3.17), lower extremity (RR, 2.05; 95% CI, 1.94–2.16), bone radionuclide (RR, 1.90; 95% CI, 1.50–2.44), and DXA imaging (RR, 1.77; 95% CI, 1.59–1.98).
Patients with RA also had significantly more conventional radiographs of the spine (RR, 1.46; 95% CI, 1.35–1.59), hip, pelvis, and sacroiliac joints (RR, 1.14; 95% CI, 1.03–1.26) (Table 1). Among patients with RA, having a positive rheumatoid factor (RF) was associated with an increased likelihood of undergoing radiologic procedures (RR, 1.05; 95% CI, 1.02, 1.07).
Similarly, among the RA patients, women underwent more imaging procedures than did men (RR, 1.20; 95% CI, 1.16–1.23). This was also true, and the results were nearly identical for patients without RA (RR, 1.20; 95% CI, 1.17–1.24). Among patients without RA, the use of radiologic procedures overall has increased somewhat in recent years (RR, 1.08; 95% CI, 1.05–1.12 for subjects with index date in 1998–2007 compared with 1988–1997), most likely due to increases in the use of advanced imaging (CT, MRI). However, among patients with RA, we did not find a significant change in the rate of radiologic procedures overall among patients with RA diagnosed in 1998 to 2007 compared with those diagnosed in 1988 to 1997 (RR, 0.98; 95% CI, 0.96–1.01).
Computed tomography/MRI of the upper and lower extremities increased in patients with RA diagnosed in 1998 to 2007 compared with those diagnosed in 1988 to 1997 (RR for upper extremity, 4.53; 95% CI, 2.69–8.62; RR for lower extremity, 2.22; 95% CI, 1.57–3.25). Whereas CT/MRI of upper and lower extremities also increased for subjects without RA whose index date was in 1998 to 2007 compared with those with index date in 1988 to 1997 (RR for upper extremity, 2.99; 95% CI, 1.70, 5.96; RR for lower extremity, 3.09; 95% CI, 1.91, 5.47), the rate of CT/MRI of upper and lower extremities among patients with RA was significantly increased compared with those without RA during the entire study period (RR for upper extremity, 1.66; 95% CI, 1.27–2.19; RR for lower extremity, 1.76; 95% CI, 1.41–2.20).
Hand/wrist radiographs were obtained in 57% of patients within 1 year after initial RA diagnosis, but during the 1 to 3 years after diagnosis, only 42% had undergone hand radiographs, and only 32% had hand radiographs during 3 to 5 years after the diagnosis. Beyond 5 years of the initial diagnosis, the percentage of patients with RA who had routine hand radiographs every 2 years plateaud around 28%. A subgroup analysis demonstrated that the cumulative incidence of patients with hand/wrist radiographs within 1 year after RA diagnosis was significantly higher in patients who were RF (62%) than in those with negative RF (45%; P < 0.001). This difference persisted during 1 to 3 years after RA diagnosis (46% in RF vs 34% in RF; P = 0.003), 3 to 5 years after RA diagnosis (37% in RF vs 23% in RF; P < 0.001), and 5 to 7 years after RA diagnosis and (34% in RF vs 25% in RF; P = 0.046). The cumulative incidence of radiologic procedures was no longer significant at 7 to 9 years after RA diagnosis (30% in RF vs 23% in RF; P = 0.15) or beyond (28% in RF vs 26% in RF at 9–11 years after RA diagnosis; P = 0.62) (Figure).
(Enlarge Image)
Figure.
Percentage of patients with RA who had at least 1 hand/wrist radiograph in a 2-year period according to years since RA diagnosis by RF positivity (circles = RF negative, squares = RF positive). Asterisks under the x axis indicate statistically significant differences between groups (P < 0.05).
Female patients with RA had more radiologic procedures than their male counterparts (RR, 1.20; 95% CI, 1.16–1.23). Similarly, DXA scans were more frequently obtained in women than in men (RR, 2.25; 95% CI, 1.89–2.71). Mammography was performed only in female patients and was less frequently obtained in women with RA than in women without RA (RR, 0.93; 95% CI, 0.88–0.99).
To account for the increased number of diagnostic modalities in the last decade, we conducted a subgroup analysis comparing the periods of 1988–1997 and 1998–2007 and found no significant difference in the number of radiologic studies between these time periods among patients with RA (RR: 0.98, 95%; CI: 0.96–1.01).
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