Applying our trigger and filtering criteria to the SAF5 database, we identified a total of 92,931, 26,797, and 34,315 Medicare beneficiaries that met our criteria for osteoarthritis of the knee, hip, or both, respectively. Table 1 describes each filter used to select patients for analysis, and Table 2 provides additional demographic information on the different cohorts.
Knee Osteoarthritis (Tables 3 and 4)
Year 1
In the first year of care following diagnosis of knee OA, 92,931 unique Medicare beneficiaries accounted for 737,640 service dates, or 41.6% of service dates in the three years following diagnosis. These patients accounted for $202M in payments in the first year of care (55.6% of payments in the three-year post-diagnosis analysis period).
In the first year of care, Surgery accounted for 57.7% ($117M) of all payments, driven by Total Knee Arthroplasty and Arthroscopy (49.6%, $100.5M and 7.0%, $14.9M of payments, respectively). Medical Services accounted for 15.8% ($31.9M) of payments, primarily driven by physical therapy (8.6%, $17.4M), arthrocentesis (3.0%, $6.0M), and hyaluronic acid injection (2.6%, $5.3M). Radiology services accounted for 8.1% ($16.4M) of payments in the first year of care, driven by X-Ray (2.1%, $4.2M) and Magnetic Resonance Imaging (MRI) (4.3%, $8.6M). Evaluation and Management services accounted for 15.5% ($31.5M) of payments, which was mostly ambulatory care (10.5%, $21.4M), inpatient professional fees (2.1%, $4.3M), and Emergency Department services (2.2%, 4.4M).
In total, 15.3% of patients underwent surgical procedures within one year of diagnosis, with 8.2% and 7.0% of patients undergoing Total Knee Arthroplasty and Arthroscopy, respectively. A substantial proportion of patients received other services, including Radiology (78.7% of patients) with 72.9% of patients receiving an X-Ray, 9.2% a CT scan, 20.9% an MRI, and 4.7% ultrasound imaging. Medical Services were used by 69.0% of patients, including behavioral health services (0.02%), hyaluronic acid injection (12.1%), corticosteroid injection (46.0%), nutrition services (0.8%), arthrocentesis (45.8%), stimulation (10.1%), PM&R services (13.0%), physical or occupational therapy (32.3%), and chiropractor services (8.9%). Evaluation and Management services were driven by ambulatory visits (94.1%), inpatient professional services (11.4%), emergency services (14.9%), and skilled nursing facilities (3.4%).
Medical Services accounted for the most service dates (35.7% of all dates in the first year of care) at 2.8 service dates per patient in the cohort. Physical therapy (18.6%, 1.5 dates per patient), arthrocentesis (10.6%, 0.8 dates per patient), and corticosteroid injection (8.1%, 0.6 dates per patient). Radiology accounted for 16.5% of service dates (1.3 dates per patient), driven by X-Ray (13%, 1.0 dates per patient) and MRI (2.9%, 0.2 dates per patient). Evaluation and Management services accounted for 21.6% of service dates in the first year of care (1.7 dates per patient), and Surgery accounted for just 2.5% of dates and 0.2 dates per patient. Additional breakdown of service dates and payments per patient is provided in Table 4.
Years 2 and 3
Surgery and Medical Services accounted for 58.5% ($53.1M) and 20.4% ($18.6M) of payments in Year 2, respectively. Total Knee Arthroplasty and Arthroscopy accounted for 54.7% ($49.7M) and 2.6% ($2.4M) of total payments, respectively. Physical therapy, arthrocentesis, and hyaluronic acid injection drove the majority of Medical Services payments, at 12.2% ($41.7M), 2.7% ($2.5M), and 2.7% ($2.5M), respectively. Evaluation and Management services accounted for just 6.7% ($6.0M) of payments. Medical Services and Radiology services accounted for the most patients seen in Year 2, at 46.0% and 34.5% of total, respectively, while 5.3% of patients underwent a surgical procedure in Year 2. Medical Services made up 42.2% of service dates, while Evaluation and Management, Radiology, and Surgery service dates decreased from Year 1 to 9.8%, 10.8%, and 1.2%, respectively.
In Year 3, Surgery accounted for 53.9% ($38.1M) of total payments (50.2%, $35.5M Total Knee Arthroplasty, 2.3%, $1.6M Arthroscopy), while the proportion of payments toward Medical Services rose to 25% ($17.7M), driven by an increased proportion of payments for hyaluronic acid injection (to 3.2%, $2.3M), arthrocentesis (to 3.1% $2.2M), and physical therapy (to 14.6%, $10.3M). The proportion of patients receiving any care decreased from Year 2, with 3.9% of patients receiving undergoing surgery, 30.1% receiving Radiology services, and 22.1% utilizing Evaluation and Management services.
Evolution of Care
In addition to the 36-month post-diagnosis period, we analyzed payments and utilization for a period of one year prior to initial diagnosis. Utilization and payments for relevant services in the first year following diagnosis increased dramatically from the prior year (56% more service dates, 163% greater payments). Total payments fell by 55% from Year 1 to Year 2 (to $90.8M), driven by a 30.8% decrease in utilization (service dates). Evaluation and Management, Surgery, and Radiology services drove this decrease in utilization and payment (72.5%, 65.2%, and 56.1% fewer service dates, respectively). Payments fell an additional 22.0% from Year 2 to Year 3 (to $70.8M), driven by an increased proportion of spending on Medical Services as compared to Surgery, Radiology, and Evaluation and Management. Total payments ($77.1M) and service dates (472,594) were similar in the year prior to diagnosis and second and third years after diagnosis ($90.8M, 509,910 service dates, and $70.8M, 524,589 service dates, respectively). The average payment per patient in the cohort was $2,182, $978 and $762, in Years 1, 2, and 3 of care following diagnosis, respectively.
Hip Osteoarthritis (Tables 5 and 6)
Year 1
In the first year of care following diagnosis of hip OA, 26,797 unique patients accounted for 202,836 service dates, or 43.6% of service dates in the three years following diagnosis. These patients accounted for $62.7M in payments in the first year of care (65.3% of payments in the three-year post-diagnosis analysis period).
In the first year of care, Surgery accounted for 60.6% ($38M) of all payments, driven by Total Hip Arthroplasty (58.8%, $36.9M). Medical Services accounted for 10.9% ($6.8M) of payments, primarily driven by physical therapy (8.6%, $5.4M). Radiology services accounted for 9.9% ($6.2M) of payments in the first year of care, driven by X-Ray (2.7%, $1.7M) and MRI (4.9%, $3.0M). Evaluation and Management services accounted for 15.7% ($9.8M) of payments, which was mostly ambulatory care (8.4%, $5.2M), inpatient professional fees (3.4%, $2.1M), and Emergency Department services (3.0%, 1.8M).
In total, 13.2% of patients underwent surgical procedures within one year of diagnosis, with 10.8% of patients undergoing Total Hip Arthroplasty. A substantial proportion of patients received other services, including Radiology (86.7% of patients) with 80.6% of patients receiving an X-Ray, 16% a CT scan, 23.1% an MRI, and 3.5% ultrasound imaging. Medical Services were used by 57.6% of patients, including behavioral health services (0.02%), corticosteroid injection (28.5%), nutrition services (0.6%), arthrocentesis (18%), stimulation (9.8%), PM&R services (13.8%), physical or occupational therapy (36%), and chiropractor services (10.1%). Evaluation and Management services were driven by ambulatory visits (88.8%), inpatient professional services (17.6%), emergency services (21.7%), and skilled nursing facilities (6.1%).
Medical Services accounted for the most service dates (32.1% of all dates in the first year of care) at 2.4 service dates per patient in the cohort. Physical therapy (20.5%, 1.6 dates per patient), stimulation (4.4%, 0.3 dates per patient), chiropractor services (6.4%, 0.5 dates per patient), and corticosteroid injection (4.8%, 0.4 dates per patient). Radiology accounted for 21% of service dates (1.3 dates per patient), driven by X-Ray (16.8%, 1.3 dates per patient) and MRI (3.5%, 0.3 dates per patient). Evaluation and Management services accounted for 18.3% of service dates in the first year of care (1.4 dates per patient), and Surgery accounted for just 2.4% of dates and 0.2 dates per patient. Additional breakdown of service dates and payments per patient is provided in Table 6.
Years 2 and 3
Surgery and Medical Services accounted for 54.1% ($10.4M) and 21.2% ($4.1M) of payments in Year 2, respectively. Total Hip Arthroplasty accounted for 52.1% ($10M) of payments. Physical Therapy drove the majority of Medical Services payments, at 16.4% ($3.2M) of payments. Evaluation and Management services accounted for just 4.5% ($0.9M) of payments. Medical Services and Radiology services accounted for the most patients seen in Year 2, at 39.9% and 33.8% of total, respectively, while 3.5% of patients underwent a surgical procedure in Year 2. Medical Services made up 40.1% of service dates, while Evaluation and Management, Radiology, and Surgery service dates decreased from Year 1 to 4.8%, 11.9%, and 0.9%, respectively.
In Year 3, Surgery accounted for 46.7% ($6.6M) of total payments (44.9%, $6.4M Total Hip Arthroplasty), while the proportion of payments toward Medical Services rose to 26.9% ($3.8M), driven by an increased proportion of payments for physical therapy (to 20.1%, $2.8M). The proportion of patients receiving any care decreased from Year 2, with 2.4% of patients receiving undergoing surgery, 28.3% receiving Radiology services, and 10.0% utilizing Evaluation and Management services.
Evolution of Care
Utilization and payments for relevant services in the first year following diagnosis increased from the prior year (42% more service dates, 127% greater payments). Total payments fell by 69% from Year 1to Year 2 (to $19.2M), driven by a 36% decrease in utilization (service dates). Evaluation and Management, Surgery, and Radiology services drove this decrease in utilization and payment (83.3%, 77.1%, and 63.6% fewer service dates, respectively). Payments fell an additional 26.4% in Year 3 (to $14.1M), driven by an increased proportion of spending on Medical Services as compared to Surgery, Radiology, and Evaluation and Management. Total payments ($27.6M) and service dates (142,760) were greater in the year prior to diagnosis and second and third years after diagnosis ($19.2M, 129,917 service dates, and $14.1M, 132,747 service dates, respectively). The average payment per patient in the population was $2,340, $717, and $528 in Years 1, 2, and 3 of care following diagnosis, respectively.
Hip and Knee Osteoarthritis (Tables 7 and 8)
Year 1
Additionally, we identified 34,315 Medicare beneficiaries with both a hip and a knee ICD–9 diagnosis code, at least one of which occurred for the first time on the payer record between 2008 and 2011. This cohort accounted for 693,912 service dates and $226M in payments over the three year post-diagnosis analysis period, as well as 119,895 service dates and $37M in the year prior to diagnosis.
In the first year of care, Surgery accounted for 63.6% ($73.5M) of all payments, driven by Total Hip Arthroplasty (33.5%, $38.7M) and Total Knee Arthroplasty (26.1%, $30.2M). Medical Services accounted for 12.3% ($14.3M) of payments, primarily driven by physical therapy (7.9%, $9.2M), arthrocentesis (1.9%, $2.2M), and hyaluronic acid injection (1.2%, $1.4M). Radiology services accounted for 7.8% ($9.0M) of payments in the first year of care, driven by X-Ray (2.2%, $2.6M) and Magnetic Resonance Imaging (MRI) (3.9%, $4.6M). Evaluation and Management services accounted for 14.1% ($16.3M) of payments, which was mostly made up of ambulatory care (8.8%, $10.2M), inpatient professional fees (2.5%, $2.9M), and Emergency Department services (2.1%, 2.4M).
In total, 20.2% of patients underwent surgical procedures within one year of diagnosis, with 6.6%, 8.7%, and 4.4% of patients undergoing Total Knee Arthroplasty, Total Hip Arthroplasty, or Arthroscopy, respectively. A substantial proportion of patients received other services, including Radiology (87% of patients) with 82% of patients receiving an X-Ray, 14.6% a CT scan, 26.8% an MRI, and 5% ultrasound imaging. Medical Services were used by 71.9% of patients, including behavioral health services (0.01%), hyaluronic acid injection (8.6%), corticosteroid injection (45.3%), nutrition services (0.7%), arthrocentesis (41.6%), stimulation (12.5%), PM&R services (16.6%), physical or occupational therapy (41.4%), and chiropractor services (11.1%). Evaluation and Management services were driven by ambulatory visits (92.6%), inpatient professional services (18.2%), emergency services (20.3%), and skilled nursing facilities (6%).
Medical Services accounted for the most service dates (50.2% of all dates in the first year of care) at 3.3 service dates per patient in the cohort. Physical therapy (29.6, 2.0 dates per patient), arthrocentesis (11.6%, 0.8 dates per patient), chiropractor services (7.8%, 0.5 dates per patient), and corticosteroid injection (10.1%, 0.7 dates per patient). Radiology accounted for 28.1% of service dates (1.9 dates per patient), driven by X-Ray (22.7%, 1.5 dates per patient) and MRI (4.8%, 0.3 dates per patient). Evaluation and Management services accounted for 30.0% of service dates in the first year of care (2.0 dates per patient), and Surgery accounted for 4.4% of dates and 0.3 dates per patient. Additional breakdown of service dates and payments per patient is provided in Table 8.
Years 2 and 3
Surgery and Medical Services accounted for 64.0% ($38.8M) and 16.4% ($10.0M) of payments in Year 2, respectively. Total Knee Arthroplasty and Total Hip Arthroplasty accounted for 30.9% ($18.7M) and 30.3% ($18.4M) of total payments, respectively. Physical Therapy, Arthrocentesis, and Hyaluronic Acid Injections drove the majority of Medical Services payments, at 10.9% ($6.6M), 2.1% ($1.2M), and 1.4% ($0.9M), respectively. Evaluation and Management services accounted for just 7.6% ($4.6M) of payments. Medical Services and Radiology accounted for the most patients seen in Year 2, at 56.7% and 54.1% of all patients, respectively, while 9.8% of patients underwent a surgical procedure in Year 2. Medical Services made up 50.0% of service dates, while the proportion of Evaluation and Management, Radiology, and Surgery service dates decreased from Year 1 to 14.5%, 17.7%, and 1.9%, respectively.
In Year 3, Surgery accounted for 61.8% ($30.8M) of total payments (29.3%, $14.6M Total Knee Arthroplasty, 29.5%, $14.7M Total Hip Arthroplasty), while the proportion of payments toward Medical Services rose to 19.5% ($9.7M), driven by an increased proportion of payments for physical therapy (to 12.7%, $6.3M). The proportion of patients receiving any care decreased from Year 2, with 7.9% of patients receiving undergoing surgery, 50.3% receiving Radiology services, and 39.0% utilizing Evaluation and Management services.
Utilization Trends
We observed several trends in service utilization and payments among patient cohorts with osteoarthritis in the knee, hip, or both. Figure 3 provides a comparison of service utilization and payment across all years. Notably, Year 1 accounted for greater utilization and payments than either Years 2 or 3 across all joints. The distribution of payments was heavily skewed toward Surgery services, which were more common in the first year of treatment, though utilization of all services declined over time.