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603 Remission and low disease activity are associated with lower health care costs in an international inception cohort of patients with systemic lupus erythematosus
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603 Remission and low disease activity are associated with lower health care costs in an international inception cohort of patients with systemic lupus erythematosus

Ann E Clarke, Manuel Francisco Ugarte-Gil, Megan RW Barber, John G Hanly, Murray B Urowitz, Yvan St Pierre, Caroline Gordon, Sang-Cheol Bae, Juanita Romero-Diaz, Jorge Sanchez-Guerrero, …
Lupus science & medicine, v 9(Suppl 3), pp A26-A28
14 Dec 2022
url
https://doi.org/10.1136/lupus-2022-lupus21century.24View
Published, Version of Record (VoR) Open

Abstract

Lupus 21st Century 2022
Background/PurposeRemission and low disease activity (LDA) are associated with decreased flares, damage, and mortality. However, little is known about the impact of disease activity states (DAS) on health care costs. We determined the independent impact of different definitions of remission and LDA on direct and indirect costs (DC, IC) in a multicentre, multi- ethnic inception cohort.MethodsPatients fulfilling revised ACR classification criteria for SLE from 33 centres in 11 countries were enrolled within 15 months of diagnosis and assessed annually. Patients with ≥2 annual assessments were included. Five mutually independent DAS were defined:1) Remission off-treatment: clinical (c) SLEDAI-2K=0, without prednisone or immunosuppressants2) Remission on-treatment: cSLEDAI-2K=0, prednisone ≤5mg/d and/or maintenance immunosuppressants3) LDA-Toronto Cohort (TC): cSLEDAI-2K≤2, without prednisone or immunosuppressants4) Modified Lupus LDA State (mLLDAS): SLEDAI-2K≤4, no activity in major organs/systems, no new disease activity, prednisone ≤7.5mg/d and/or maintenance immunosuppressants5) Active: all remaining assessmentsAntimalarials were permitted in all DAS. At each assessment, patients were stratified into 1 DAS; if >1 definition was fulfilled per assessment, the patient was stratified into the most stringent. The proportion of time patients were in a specific DAS at each assessment since cohort entry was determined.At each assessment, annual DC and IC were based on health resource use and lost workforce/non-workforce productivity over the preceding year. Resource use was costed using 2021 Canadian prices and lost productivity using Statistics Canada age-and-sex-matched wages.To examine the association between the proportion of time in a specific DAS at each assessment since cohort entry and annual DC and IC, multivariable random-effects linear regression modelling was used. Potential covariates included age at diagnosis, disease duration, sex, race/ethnicity, education, region, smoking, and alcohol use.Results1631 patients (88.7% female, 48.9% White, mean age at diagnosis 34.5) were followed for a mean of 7.7 (SD 4.7) years (table 1, Panel A). Across 12,281 assessments, 49.3% were classified as active (table 1, Panel B). Patients spending <25% vs 75-100% of their time since cohort entry in an active DAS had lower annual DC and IC (DC $4042 vs $9101, difference - $5060, 95%CI -$5983, -$4136; IC $21,922 vs $32,049, difference -$10,127, 95% -$16,754, - $3499) (table 2, Panel B&C).In multivariable models, remission and LDA (per 25% increase in time spent in specified DAS vs active) were associated with lower annual DC and IC: remission off-treatment (DC -$1296, 95%CI -$1800, -$792; IC -$3353, 95%CI -$5382, -$1323), remission on-treatment (DC -$987, 95%CI -$1550, -$424; IC -$3508, 95%CI -$5761, -$1256), LDA-TC (DC -$1037, 95%CI -$1853, -$222; IC -$3229, 95%CI -$5681, -$778) and mLLDAS (DC -$1307, 95%CI -$2194, -$420; IC - $3822, 95%CI -$6309, $-1334) (table 3, Model B). There were no differences in costs between remission and LDA.ConclusionsRemission and LDA are associated with lower costs, likely mediated through the known association of these DAS with more favourable clinical outcomes.Abstract 603 Table 1Patient Characteristics Panel A. At baseline (Number of patients = 1631) Characteristic Number of Patients (%) or Mean (SD) Female sex 1446 (88.7%) Age at diagnosis, years 34.5 (13.3) Ethnicity  White, North American 509 (31.2%)  White, other 289 (17.7%)  Black 268 (16.4%)  Hispanic 258 (15.8%)  Asian 250 (15.3%)  Other 57 (3.5%) Disease duration at baseline, months 5.6 (4.2) Panel B. Follow-up (Number of assessments = 12,281) Disease Activity State Number of Annual Assessments, (%) Number of Patients,* (%) Remission Off-Treatment 2566 (20.8%) 612 (37.5%) Remission On-Treatment 2421 (19.7%) 771 (47.3%) LDA-TC 556 (4.5%) 277 (17.0%) mLLDAS 680 (5.5%) 430 (26.4%) Active 6058 (49.3%) 1446 (88.7%) *The number of patients exceeds 1631 as a single patient may have multiple disease activity states during the study and will contribute assessments to multiple states.LDA-TC: Low Disease Activity-Toronto Cohort; mLLDAS: Modified Lupus Low Disease Activity StateAbstract 603 Table 2Annual Direct and Indirect Costs Stratified by Proportion of Time since Cohort Entry in Specified Disease Activity States Panel A. Distribution of Assessments based on Percentage of Time in Specified Disease Activity States, n (%) % of time since cohort entry in specified state Remission Off- Treatment Remission On- Treatment LDA - TC mLLDAS Active < 25% 9215 (75.0) 9381 (76.4) 11355 (92.5) 11409 (92.9) 2701 (22.0) 25 - <50% 1184 (9.6) 1707 (13.9) 535 (4.4) 677 (5.5) 2286 (18.6) 50 - <75% 943 (7.7) 918 (7.5) 230 (1.9) 135 (1.1) 2248 (18.3) 75 - 100% 939 (7.6) 275 (2.2) 161 (1.3) 60 (0.5) 5046 (41.1) Panel B. Annual Direct Costs (in 2021 Canadian dollars), mean (95% CI) < 25% 7812 (7275, 8348) 7055 (6578, 7532) 7085 (6644, 7526) 6996 (6555, 7437) 4042 (3540, 4543) 25 - <50% 5131 (4328, 5934) 7033 (5794, 8272) 4604 (3327, 5880) 4997 (4237, 5757) 4614 (4157, 5070) 50 - <75% 3650 (3016, 4284) 5026 (4289, 5764) 3328 (1967, 4688) 6357 (4093, 8621) 7633 (6503, 8763) 75 - 100% 3183 (2511, 3855) 5485 (4150, 6820) 3789 (1953, 5626) 4012 (2030, 5995) 9101 (8303, 9899) Panel C. Annual Indirect Costs (in 2021 Canadian dollars), mean (95%CI) < 25% 29667 (25531, 33803) 29207 (25094, 33319) 29125 (25364, 32885) 29168 (25387, 32950) 21922 (16803, 27041) 25 - <50% 29074 (24217, 33931) 29137 (25731, 32544) 25792 (19158, 32425) 23965 (18644, 29285) 27122 (23233, 31010) 50 - <75% 26138 (21812, 30463) 25453 (20486, 30420) 22276 (15112, 29441) 18895 (8347, 29443) 30843 (27061, 34625) 75 - 100% 21100 (13680, 28519) 18807 (9964, 27650) 16344 (4057, 28630) 11821 (-11681, 35322) 32049 (26573, 37525) LDA-TC: Low Disease Activity-Toronto Cohort; mLLDAS: Modified Lupus Low Disease Activity StateAbstract 603 Table 3Multivariable Models of the Impact of Disease Activity States Since Cohort Entry on Annual Direct and Indirect Costs Model A Annual Direct Costs, coefficient (95%CI) Annual Indirect Costs, coefficient (95%CI) Active state* 1161 (743, 1579) 3390 (1424, 5356) Disease duration 333 (249, 417) 1346 (652, 2040) White race/ethnicity -2049 (-3356, -742) - Residing outside North America - -13657 (-19202, -8112) Model B Remission Off-Treatment** -1296 (-1800, -792) -3353 (-5382, -1323) Remission On-Treatment -987 (-1550, -424) -3508 (-5761, -1256) LDA-TC -1037 (-1853, -222) -3229 (-5681, -778) mLLDAS -1307 (-2194, -420) -3822 (-6309, -1334) Disease duration 330 (245, 415) 1353 (662, 2044) White race/ethnicity -1996 (-3319, -674) - Residing outside North America - -13569 (-19040, -8097) Difference between disease activity state coefficients (95%CI) Remission On vs Remission Off-Treatment 309 (-304, 921) -156 (-1680, 1369) LDA-TC vs Remission Off-Treatment 259 (-660, 1117) 123 (-1812, 2058) LDA-TC vs Remission On-Treatment -50 (-924, 824) 279 (-1400, 1959) mLLDAS vs Remission Off-Treatment -11 (-902, 881) -469 (-2259, 1321) mLLDAS vs Remission On-Treatment -320 (-1255, 616) -313 (-2741, 2115) mLLDAS vs LDA-TC -270 (-1365, 826) -592 (-3056, 1872) *Reference group for active state in Model A is all other disease activity states** Reference group for all disease activity states in Model B is active stateLDA-TC: Low disease activity – Toronto Cohort; mLLDAS: modified Lupus Low Disease Activity State

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