POS1154 OUTCOMES AND RESOURCE UTILIZATION AFTER TOTAL HIP ARTHROPLASTY IN PATIENTS WITH CALCIUM PYROPHOSPHATE DEPOSITION DISEASE

Background Total hip arthroplasty (THA) is a safe and effective treatment option in patients with advanced degenerative joint disease who have failed conservative management. Calcium pyrophosphate deposition disease (CPPD) is a common crystal-induced arthritis in older adults characterized by the deposition of calcium pyrophosphate crystals in the articular and periarticular tissues 1 . CPPD might manifested with acute and chronic arthritis that can lead to joint damage and the need for joint replacement. To our knowledge, no previous studies investigated the outcomes of CPPD patients who underwent THA. Objectives We aim to examine the mortality, in-hospital complications, and resource utilization following THA in patients with and without CPPD. Methods We queried the US National Inpatient Sample (NIS) database to identify patients who underwent THA between 2006 and 2014. The ICD-9 code 81.51 was used to identify the patients who underwent THA and of those, we classified 2 groups of patients: (i) those with ICD-9 codes defining CPPD (275.49 and 712.1–712.39) and (ii) those without any CPPD code. Data collection included patient demographics and comorbidities. Outcomes post-THA were in-hospital mortality, hospital length of stay, hospital charges, and discharge disposition. Associations between CPPD and specific morbidity were evaluated with chi-square tests. T tests were used for continuous variables. Results Among the 4,111,808 (adjusted for sampling weight) patients who underwent THA between 2006 and 2014, 6198 (0.15%) had CPPD, with a mean age of 77 years and 65.2% were females (Table 1). CPPD patients were more likely to be older (mean age 77 vs 72.7; p<0.001) than non-CPPD patients. Comorbidities more frequently observed among CPPD patients included chronic kidney disease, osteoarthritis, rheumatoid arthritis, gout, hyperparathyroidism and hypomagnesemia. Further, Charlson Comorbidity Index scores ≥ 2 was more frequent seen in CPPD (96.1% vs 89.1%, p <0.001). The in-hospital mortality post-THA was lower in the CPPD patients (0.76% vs 1.72%, p <0.001). THA in CPPD patients was associated with a longer mean length of stay than those without CPPD (6 vs 5.1 days; p <0.001) while mean total charges were not statistically different between the 2 groups (p=0.344). CPPD patients were more likely to be discharged to rehabilitation or other nursing facilities (p<0.001). Table 1. Demographics, clinical characteristics, outcomes and resource utilization of patients with and without CPPD who underwent hip arthroplasty between 2006-2014. No CPDD, n (%) (N=4105610) CPPD, n (%) (N=6198) P-value* Age in years at admission, median (mean ± SD) 75 (72.7 ± 31.5) 80 (77.0 ± 24.2) <0.001† Female 2507971 (61.1) 3979 (64.2) <0.001 Chronic kidney disease 516688 (12.5) 1154 (18.6) <0.001 Osteoarthritis 684171 (16.6) 1280(20.6) < 0.001 Gout 139648 (3.4) 330 (5.3) <0.001 Rheumatoid arthritis 199175 (4.8) 478(7.7) <0.001 Hyperparathyroidism 7959 (0.1) 24(0.3) <0.001 Hypomagnesemia 100390 (2.45) 239 (3.86) <0.001 Charlson Comorbidity Index score ≥ 2 3659906 (89.1) 5961(96.1) <0.001 Outcomes/Resource utilization Length of stay, (mean ± SD) 5.15 ± 11.72 6.04 ± 13.91 <0.001† Total hospital charges, (mean ± SD) $ 41284 ± 108238 ($ 42757 ± 124894) 0.344† Death during hospitalization 70706 (1.7) 47 (0.7) <0.001† Discharge Disposition Home (including home health care) 2653860 (64.7) 3558 (57.4) <0.001 All others§ 1447312 (35.3) 2635 (42.5) <0.001 *Chi-square P except †t-test §All others include transfer to nursing or rehabilitation facility. Conclusion CPPD patients who underwent THA were more likely to be older, with a higher comorbidity burden, longer length of stay, and discharged to a non-home setting, than non-CPPD patients. References [1]Rosenthal AK, Ryan LM. Calcium Pyrophosphate Deposition Disease. N Engl J Med. 2016;d 374(26):2575-84. Disclosure of Interests None declared