SAT0434 MINIMAL CLINICALLY IMPORTANT DIFFERENCE IN OUTCOME MEASURES FOR USE IN CLINICAL CARE AND PRAGMATIC TRIALS IN PsA

Background:

While several outcome measures have been studied for use in clinical studies of psoriatic arthritis, little is known about thresholds of meaning such as minimal clinically important improvement (MCII).

Objectives:

To investigate the distribution of scores for candidate outcome measures for pragmatic trials in PsA and to calculate the MCII for each outcome measure.

Methods:

We performed a longitudinal cohort study within the Psoriatic Arthritis Research Consortium (PARC), a multi-center study based in the US. Patients completed validated PROs (patient reported outcomes) and rheumatologists completed skin, joint, enthesis and dactylitis scores at therapy initiation and follow up 12-16 weeks later. In addition, patients completed a global assessment of response at the follow up visit, categorizing their status as improved, stayed the same, or worsened and then ratied the importance of the change on a scale from 0-7.1We then calculated and plotted the change in each of the following measures: Routine Assessment of Patient Index Data (RAPID3), clinical Disease Activity of Psoriatic Arthritis (cDAPSA), Patient Reported Outcome Measure Information System (PROMIS) Global Health short form (10a) physical health (PH) subscore, patient pain assessment, patient global assessment (0-10 NRS), and physician global assessments (0-10 NRS) of the joints and overall. We calculated the MCII as the mean change in score (with 95% confidence interval) among patients who reported improvement and rated the level of improvement as “almost none/hardly at all” or “a little important.” Additionally, we calculated Spearman’s correlation coefficients between the measures and the global assessment of response.

Results:

Among 148 unique patients, 233 therapy change visits were eligible for analysis. The average age was 52.5 years, 52% were female and mean BMI was 29.6. Baseline RAPID3 was 11.1 (SD 6), cDAPSA 17.9 (SD 13.9), PROMIS PH 42 (SD 8), patient global 4.2 (SD 2.5), TJC 5.9 (SD 7.5), and SJC 2.9 (SD 4.5). TNFi comprised 61% of drug initiations, 21% were IL17i and the remainder were other biologics and oral systemic therapies. At follow up, 63 (27%) patients rated themselves as improved whereas 103 (44%) stayed the same and 67 (29%) reported worsening. The mean change in each measure by patient-reported response (improved, stayed the same, or worsened) are shown in Figures 1A & B. In general, the mean score increased from ‘improved’ to ‘worsened’ as expected (with the exception of PROMIS PH which declines given a different direction of scoring). The MCII for each measure was as follows: RAPID3 -1.8 (-4.1 to 0.5), Patient Global -0.6 (-1.6 to 0.4), Physician Global -1 (-1.9 to -0.1), cDAPSA -5.7 (-9.8 to -1.7), and PROMIS PH 1.9 (-2.1 to 5.8). Correlation for each measure with the global assessment of response were: RAPID3 0.48, Patient Global 0.37, Physician Global 0.39, cDAPSA 0.51, and PROMIS PH 0.39.

Figure 1

A. Distribution of change (median, IQR) in RAPID3, Physician Global, Patient Global, PROMIS10a physical therapy by patient reported response.

Conclusion:

This is the first study to test thresholds of meaning for these particular measures in PsA. The MCII values are relatively low for all outcome measures. This may be related to the relatively low disease activity at baseline but is consistent with patients seen in clinical practice initiating therapy.2

References:

[1]Ward MM et al. J Clinical Epi 2014;2Ward MM et al. J Clinical Epi 2015

Figure 2

B. Distribution of change (median, IQR) in clinical DAPSA by patient reported response.

Disclosure of Interests:

Alexis Ogdie Grant/research support from: Pfizer, Novartis, Consultant of: Abbvie, Amgen, BMS, Celgene, Corrona, Janssen, Lilly, Pfizer, Novartis, M Elaine Husni Grant/research support from: Pfizer, Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Janssen, Novartis, Regeneron, and UCB, Jose Scher Consultant of: Novartis, Janssen, UCB, Sanofi., Ethan Craig: None declared, Soumya Reddy Grant/research support from: Amgen

Celgene

Abbvie, Consultant of: Amgen

Pfizer

Novartis

Jaansen

UCB, Jessica A. Walsh Grant/research support from: AbbVie, Pfizer, Janssen, Consultant of: AbbVie, Novartis, Eli Lilly and Company, UCB

Syncytiotrophoblast extracellular microvesicle profiles in maternal circulation for noninvasive diagnosis of preeclampsia

Preeclampsia is the most common placental pathology in pregnant females, with increased morbidity and mortality incurred on the mother and the fetus. There is a need for improved biomarkers for diagnosis and monitoring of this condition. Placental syncytiotrophoblasts at the maternal-fetal interface release nanoparticles, including extracellular microvesicles, into the maternal blood during pregnancy. Syncytiotrophoblast extracellular microvesicles (STEVs) are being studied for their diagnostic potential and for their potential physiologic role in preeclampsia. We hypothesized that STEV profiles in maternal circulation would be altered under conditions of preeclampsia compared to normal pregnancy. Extracellular vesicles (EVs) released by BeWo cells in vitro showed high expression of syncytin-1, but no plac1 expression, demonstrating that trophoblast cell EVs express syncytin-1 on their surface. Placental alkaline phosphatase also showed high expression on BeWo EVs, but due to concern for cross reactivity to highly prevalent isoforms of intestinal and bone alkaline phosphatase, we utilized syncytin-1 as a marker for STEVs. In vivo, syncytin-1 protein expression was confirmed in maternal plasma EVs from Control and Preeclampsia subjects by Western blot, and overall, lower expression was noted in samples from patients with preeclampsia (n = 8). By nanoparticle analysis, EV profiles from Control and Preeclampsia groups showed similar total plasma EV quantities (p = 0.313) and size distribution (p = 0.415), but STEV quantitative signal, marked by syncytin-1 specific EVs, was significantly decreased in the Preeclampsia group (p = 2.8 × 10⁻¹¹). Receiver operating characteristic curve demonstrated that STEV signal threshold cut-off of <0.316 was 95.2% sensitive and 95.6% specific for diagnosis of preeclampsia in this cohort (area under curve = 0.975 ± 0.020). In conclusion, we report that the syncytin-1 expressing EV profiles in maternal plasma might serve as a placental tissue specific biomarker for preeclampsia.

P1460Seismocardiographic measurement of systolic time intervals in left ventricular dysfunction: validation with transthoracic echo

Background

Systolic time intervals (STI) measured using Transthoracic Echo (TTE) have been shown to be sensitive indicators of contractile performance, but TTE is limited to a hospital setting. Recent advances in technology have enabled the simultaneous measurement of Electrocardiograms (ECG) and Seismocardiograms (SCG) using wearable devices. However, the use SCG to measure STIs has not been validated in a mobile setting, or on pathological subjects.

Purpose

To test the validity of an automated algorithm for measuring STIs using a wearable device recording ECG and SCG, in subjects with varying degrees of left ventricular dysfunction.

Methods

179 Patients with suspected left ventricular dysfunction were assessed using TTE performed by a Cardiologist. Patients were simultaneously fitted with a novel wearable device worn on a chest strap, recording SCG and single-lead ECG data, while the cardiologist measured the pre-ejection period (PEP) and left ventricular ejection time (LVET) with the patient in a supine position. Of these subjects 29 (16.2%) were diagnosed with Dilated cardiomyopathy (DCM), and 109 (60.8%) had Ischemic Heart disease.

The SCG and ECG data recorded on the wearable device was then analysed using a peak-detection algorithm, which detected the Q,R,S points on the ECG, and then determined the 4 most prominent peaks in the SCG signal corresponding to each R-peak. Heart rate, patient's age, gender and SCG time intervals were then used in a DecisionTree algorithm to determine the values of PEP and LVET, which were were then compared against those determined by the cardiologist using TTE.

Results

The correlation coefficient (r2) between PEP calculated using TTE, and the values obtained from the algorithm analyzing SCG data was 0.92 while the mean error was 7.47%. The r2 between the LVET calculated using the TTE and the algorithm was 0.75, while the mean error was 8.53% (p-value<0.001 for all cases).

Results All Subjects With IHD Without IHD With DCM Without DCM Number of Subjects 178 109 69 29 149 PEP (r2) 0.92 0.89 0.94 0.88 0.91 PEP (% age error) 7.47 7.50 7.42 6.99 7.56 LVET (r2) 0.75 0.81 0.66 0.55 0.83 LVET (% age error) 8.53 6.69 11.4 20.42 6.16 DCM, Dilate Cardiomyopathy; IHD, Ischemic Heart Disease.

ECG + SCG signals for a DCM patient

Conclusion

The algorithm-derived STIs measured by SCG correlate well with those measured by TTE across most patient groups, including those with Dilated Cardiomyopathy and Ischemic Heart Disease, opening prospects for continuous remote monitoring of STIs in a mobile setting.

Acknowledgement/Funding

Fourth Frontier Technologies

Noninvasive diagnosis of recurrent autoimmune type 1 diabetes after islet cell transplantation

Islet cell transplantation is curative therapy for patients with complicated autoimmune type 1 diabetes (T1D). We report the diagnostic potential of circulating transplant islet-specific exosomes to noninvasively distinguish pancreatic β cell injury secondary to recurrent autoimmunity vs immunologic rejection. A T1D patient with hypoglycemic unawareness underwent islet transplantation and maintained normoglycemia until posttransplant day 1098 before requiring exogenous insulin. Plasma analysis showed decreased donor islet exosome quantities on day 1001, before hyperglycemia onset. This drop in islet exosome quantity signified islet injury, but did not distinguish injury type. However, analysis of purified transplant islet exosome cargoes showed decrease in insulin-containing exosomes, but not glucagon-containing exosomes, indicating selective destruction of transplanted β cells secondary to recurrent T1D autoimmunity. Furthermore, donor islet exosome cargo analysis showed time-specific increase in islet autoantigen, glutamic acid decarboxylase 65 (GAD65), implicated in T1D autoimmunity. Time-matched analysis of plasma transplant islet exosomes in 3 control subjects undergoing islet cell transplantation failed to show changes in islet exosome quantities or intraexosomal cargo expression of insulin, glucagon, and GAD65. This is the first report of noninvasive diagnosis of recurrent autoimmunity after islet cell transplantation, suggesting that transplant tissue exosome platform may serve as a biomarker in islet transplant diagnostics.

A novel study to examine the association of PCSK9 rs505151 polymorphism and coronary artery disease in north Indian population

There is a drastic increase in the number of people suffering from coronary artery disease (CAD) worldwide with Indians being no exception. Being a developing country and experiencing a dramatic shift in lifestyle and eating habits, urbanization and industrialization, all these factors have collectively predisposed the Indian population towards CAD and the prevalence data arequite alarming. Genetic studies have disclosed the role of genes in CAD susceptibility and severity. One such gene is proprotein convertase subtilisin/kexin type 9 (PCSK9) which is sought to modulate the cholesterol levels and hence, has implications in CAD. We aim to explore the association of PCSK9 A/G (rs505151) polymorphism and hence, the susceptibility towards CAD in the north Indian population. Five-hundred angiographically confirmed CAD patients and 500 healthy individuals as control were genotyped by polymerase chain reaction-restriction fragment length polymorphism. Statistical analysis revealed a significant association with the G allele with odds ratio (OR)=1.50, 95% confidence interval (CI)=1.22-1.85 and P=0.000. Also, a strong association was observedfor CAD risk with OR=1.590, 95% CI=1.106-2.284 and P=0.012. However, the homozygous GG mutant genotype was found to be completely absent from our population. Analysis of the dominant model also revealed an association with CAD risk. Our work demonstrated for the first time the association of PCSK9 A/G (rs505151) polymorphism with CAD risk in the north Indian population.