POS1443 IDENTIFYING THE NEW EMERGENCE OF RACIAL DISPARITIES IN GOUT OVER THE PAST 3 DECADES – US NATIONAL SURVEY AND PROSPECTIVE COHORT DATA

Background

Several studies published after 2010 reported a higher frequency of gout and hyperuricemia among US Blacks than Whites.1-4 However, Blacks (in the US and Africa) were previously thought to suffer gout less often than Whites.5 We hypothesized that the racial disparity in Blacks emerged over the past several decades, with flipped prevalence between the two races.

Objectives

To assess trends in racial differences in gout prevalence in the US using both national survey and cohort study data over the past 3 decades.

Methods

Using data from the NHANES (National Health and Nutrition Examination Survey) III (1988-1994) and latest decade (2007-2016), and data from 5 examination periods in the ARIC (Atherosclerosis Risk in Communities) Study between 1988 through 2013, we compared age- and sex-adjusted prevalences and odds ratios (OR) to determine the trend of racial differences in gout prevalence between Blacks and Whites. A time-race interaction term was used to assess differences in the rate of change between the two races.

Results

Among Whites, the sex- and age-standardised prevalence of gout in the NHANES rose from 2.8% (95% CI: 2.4 to 3.2) in 1988-94 to 3.7% (3.2 to 4.1) in 2007/16. Prevalence of gout among Blacks was lower than Whites in 1988-94 (2.6% [2.2 to 3.0]) but rose more sharply over the subsequent decades (p for race-time interaction=0.003), and in 2007/16 came to exceed that of Whites (5.0% [4.4 to 5.6]).

Corresponding age-sex-adjusted ORs for gout in Blacks vs. Whites were 0.93 (0.73 to 1.17) in 1988-94, increasing to 1.46 (1.22 to 1.74) in 2007/16 (Table 1). This disproportionate rise in gout prevalence among Blacks tended to be more prominent among women (OR 1.81 [1.29 to 2.53]) than men (OR 1.26 [1.02 to 1.55]; p for race-time interactions of 0.002 and 0.01, respectively). Similar trends were observed in the ARIC cohort, where the OR for gout among Blacks vs. Whites rose progressively from 0.82 (0.65 to 1.02) in 1987-89 to 1.81 (1.49 to 2.19) in 2011-13.

Table 1.

Temporal Trend of Racial Disparity in Gout Prevalence in NHANES Survey and the ARIC Study Cohort, overall and by sex

Odds Ratio (95% CI) for Gout Among Blacks vs. WhitesOVERALLNHANES1988-19942007-2016Age- and sex-adjusted0.93(0.73 to 1.17)1.46(1.22 to 1.74)ARICVisit 1: 1987-89Visit 2: 1990-92Visit 3: 1993-95Visit 4: 1996-98Visit 5: 2011-13Age- and sex-adjusted0.82(0.65 to 1.02)0.99(0.81 to 1.22)1.24(1.03 to 1.50)1.60(1.35 to 1.90)1.81(1.49 to 2.19)WOMENNHANES1988-19942007-2016Age-adjusted0.98(0.65 to 1.47)1.81(1.29 to 2.53)ARICVisit 1: 1987-89Visit 2: 1990-92Visit 3: 1993-95Visit 4: 1996-98Visit 5: 2011-13Age-adjusted0.92(0.64 to 1.32)1.14(0.82 to 1.59)1.45 (1.07 to 1.96)1.89 (1.45 to 2.46)2.28(1.73 to 3.01)MENNHANES1988-19942007-2016Age-adjusted0.91(0.68 to 1.21)1.26 (1.02 to 1.55)ARICVisit 1: 1987-89Visit 2: 1990-92Visit 3: 1993-95Visit 4: 1996-98Visit 5: 2011-13Age-adjusted0.73 (0.54 to 0.97)0.87 (0.66 to 1.14)1.03(0.79 to 1.33)1.29(1.02 to 1.64)1.34(1.00 to 1.78)

Conclusion

Gout prevalence tended to be lower in Blacks than Whites until late 80’s, then rose and surpassed that of Whites over the past several decades. These trends closely parallel the worsening obesity epidemic during this period,6 particularly in Blacks, partly due to enhanced Western lifestyle. Gout risk genetic profile change would not contribute to this emergence of racial differences, particularly among the same individuals in ARIC, although it remains to be clarified whether Blacks carry genetic profiles that enhance the effect of lifestyle risk factors for gout.

References

[1]PMID 22225548 (2012)

[2]PMID 24330409 (2013)

[3]PMID 24335384 (2014)

[4]PMID: 30618180 (2019)

[5]NEJM PMID: 15014177

[6]JAMA PMID: 12365955

Disclosure of Interests

Natalie McCormick: None declared, Leo Lu: None declared, Chio Yokose: None declared, Amit Joshi: None declared, Yuqing Zhang: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, and Vaxart., Grant/research support from: Ironwood and Horizon

POS0280 EXCESS RISK OF ALL-CAUSE AND CARDIOVASCULAR MORTALITY IN FEMALES WITH GOUT – A PROSPECTIVE COHORT STUDY OF 105,502 WOMEN

Background

Despite the disproportionately worsening disease burden of female gout in recent years1 and its frequent associations with key cardiovascular risk factors (more often than male gout2,3), there remains a paucity of specific data about female gout, particularly about its impact on mortality and fatal coronary heart disease (CHD).

Objectives

To prospectively examine the relation of female gout and risk of all-cause and cardiovascular and coronary heart disease-specific deaths.

Methods

Using data from the Nurses’ Health Study (NHS), an ongoing prospective cohort study in which female nurses in the United States completed detailed mailed questionnaires regarding their medical history, lifestyle, and other risk factors at baseline and every two years thereafter, we prospectively analyzed the relation between gout status at baseline and during the follow-up period and the risk of all-cause and cardiovascular mortality using Cox proportional hazards regression to adjust for cardiovascular risk factors such as comorbidities, body mass index, postmenopausal status, medication use, and dietary factors.

Results

The analysis included 105,502 women without gout and 1602 women with gout. Women with gout at baseline in 1982 tended to be older (mean age 54 vs. 50 years), and more likely to report a history of hypertension (44% vs. 22%), hypercholesterolemia (17% vs. 8%), and diabetes (11% vs. 6%). During 24 years of follow-up, we documented 15,255 deaths from all causes, including 3,128 deaths from cardiovascular disease (CVD) and 1,405 deaths from coronary heart disease (CHD). Compared to women without history of gout or CHD at baseline, the multivariable relative risks (RRs) among women with history of gout at baseline were 1.33 (95% CI, 1.21 to 1.46) for total mortality, 1.40 (95% CI, 1.17 to 1.67) for CVD deaths, and 1.49 (95% CI, 1.17 to 1.91) for fatal CHD (Table 1). The corresponding RRs for gout at baseline and during the follow-up were 1.33 (95% CI, 1.23 to 1.44), 1.43 (95% CI, 1.24 to 1.66), and 1.34 (95% CI, 1.08 to 1.66), respectively.

Table 1.

Relative Risks of Death from All-Causes, Cardiovascular Disease, and Coronary Heart Disease According to Gout Status at Baseline in 1982 in the Nurses’ Health Study

No CHDNo GoutGoutDeaths from all causesCases, n14,810445Age-adjusted RR (95% CI)1.01.58 (1.43, 1.73)Multivariable-adjusted* RR (95% CI)1.01.33 (1.21, 1.46)All cardiovascular deathsCases, n3,001127Age-adjusted RR (95% CI)1.02.06 (1.72, 2.46)Multivariable-adjusted* RR (95% CI)1.01.40 (1.17, 1.67)Fatal CHDCases, n1,33570Age-adjusted RR (95% CI)1.02.53 (1.99, 3.22)Multivariable-adjusted* RR (95% CI)1.01.49 (1.17, 1.91)

*Adjusted for age (continuous), history of hypertension, history of hypercholesterolemia, history of diabetes, aspirin use (yes, no), diuretic use (yes, no), smoking (never, past, current <15, current ≥15 cigarettes/day), body mass index (<23, 23-24.9, 25-29.9, 30-34.9, ≥35), physical activity (quintile), alcohol intake (nondrinker, <5, 5-9, 10-29, ≥30g/day), family history of MI (yes, no), menopausal status (premenopause, post menopause), hormone replacement therapy use (premenopause, never user, current user, past user). total energy intake (quintile), trans fat (quintile), dietary cholesterol (quintile), protein (quintile), linoleic fatty acid (quintile), and ratio of polyunsaturated fat/saturated fat.

CHD = coronary heart disease; CI = confidence interval; RR = relative risk.

Conclusion

These prospective data indicate that women with gout have a higher risk of all-cause mortality, which is primarily driven by higher risk of CVD deaths. These findings closely agree with the UK general population data of both sexes that showed unclosing mortality gap over the past two decades.4 Together, these findings provide support for rigorous cardiovascular risk factor modification specifically in female gout to help curtail the rising disease burden of gout worldwide.1

References

[1]Xia et al., PMID 31624843

[2]Puig et al., PMID 2012455

[3]Harrold et al., PMID 16644784

[4]Fisher et al., PMID 28122760

Disclosure of Interests

Chio Yokose: None declared, Natalie McCormick: None declared, Na Lu: None declared, Amit Joshi: None declared, Gary Curhan Consultant of: AstraZeneca, Allena Pharmaceuticals, Shire/Takeda, Dicerna, and Orfan, Grant/research support from: Decibel Therapeutics, Employee of: Chief Medical Officer at OM1, Inc., Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, and Vaxart, Grant/research support from: Ironwood and Horizon

POS0155 WHAT DRIVES RACIAL DISPARITIES IN GOUT IN THE US? – POPULATION-BASED, SEX-SPECIFIC, CASUAL MEDIATION ANALYSIS

Background

Traditionally viewed as a disease of White men, global frequency and disability burden of female gout are rising disproportionately to male gout.1 Moreover, emerging US cohort data suggest gout and hyperuricemia impart larger burdens on Black adults than Whites.2 These racial disparities may be largely attributable to differences in non-genetic, mainly modifiable gout risk factors e.g., BMI, diet,3,4 and chronic kidney disease (CKD). However, national-level, general population data on racial differences in burden of gout, and potential mediators, are lacking.

Objectives

To determine and quantify sex-specific mediators of racial disparities in gout prevalence among a nationally representative sample of US adults.

Methods

Using recent decadal data (2007-2016) on physician-diagnosed gout and hyperuricemia from the National Health and Nutrition Examination Survey, we compared contemporary sex- and race-specific prevalences and conducted sequential causal mediation analysis (adjusting for upstream mediators following causal pathways)5 to determine the proportion of the racial differences attributable to 7 potentially mediating social and clinical factors (see DAG in Figure 1): low education, poverty, body mass index (BMI), alcohol, poor quality diet (poor DASH adherence), diuretic use, and CKD (eGFR <60 mL/min, using the latest equations that do not include a coefficient for Black race6, per National Kidney Foundation and American Society of Nephrology recommendations.7)

Results

Age standardised prevalence of gout was 3.5% and 2.0% in Black and White women, respectively (age-adjusted OR =1.8 [95% CI: 1.3 to 2.5]), and 7.0% and 5.4% in Black and White men (age-adjusted OR =1.3 [1.0 to 1.6]). Most risk factors were more frequent/elevated in Blacks than Whites, except alcohol consumption, which was lower in Blacks (both sexes). BMI levels and poverty were higher in Black women, but similar between Black and White men.

Largest mediating factor of excess gout cases among Black women was excess BMI, accounting for 56% of the racial difference (independent of education, poverty, diet, and alcohol), followed by CKD (24%), poverty (17%), and poor diet (12%) (see Table 1).

Table 1.

Indirect (mediation) effects of potential mediators, using sequential mediation analysis, for the association between Black race and odds of gout in US women and men.

WOMENMENEffect Estimate (OR), 95% CIProportion Mediated, %Effect Estimate (OR), 95% CIProportion Mediated, %Indirect (Mediation) EffectEducation (high school or less)1.01 (0.98 to 1.03)2.4%1.01 (0.98 to 1.03)3.3%Poverty1.07 (1.04 to 1.10)16.9%1.00 (0.99 to 1.00)0.53%Alcohol consumption (# drinks/week, continuous)0.99 (0.96 to 1.01)-3.4%0.99 (0.98 to 1.00)-4.5%DASH diet score (continuous; higher scores = ↓ adherence)1.05 (0.96 to 1.01)12.0%1.05 (1.01 to 1.10)19.8%Body mass index (continuous)1.25 (1.14 to 1.37)55.9%1.03 (1.02 to 1.04)11.9%Diuretic use1.03 (1.01 to 1.05)7.6%1.04 (1.02 to 1.06)14.2%Chronic kidney disease1.10 (1.04 to 1.16)23.9%1.12 (1.08 to 1.17)45.6%Direct Effect0.94 (0.68 to 1.30)a−15.2%1.02 (0.83 to 1.26)b9.2%Total Effect1.49 (1.12 to 1.98)100%1.29 (1.05 to 1.57)100%

DASH=Dietary Approaches to Stop Hypertension;

ap=0.52,

bp=0.83

Among men, CKD was the largest mediator (46%), followed by poor diet (20%) and diuretic use (14%). BMI (12%) and poverty (0.5%) mediated smaller proportions of the racial difference among men compared to women. Mediators of racial differences in hyperuricemia closely agreed with gout results.

Conclusion

Contrasting with historical views, gout is more frequent among Black adults in the US than their White counterparts, especially women (two-times greater in Black women vs. White). Culturally informed efforts to reduce these disparities should focus on excess adiposity, diet quality, and kidney disease while recognising the impact of poverty in female gout.

References

[1]Xia; PMID 31624843

[2]PMID 24335384

[3]Rai BMJ PMID 28487277

[4]Yokose JAMA IM (2022)

[5]VanderWeele; PMID 25580377

[6]NEJM PMID 34554658

[7]JASN PMID 34556489

Disclosure of Interests

Natalie McCormick: None declared, Leo Lu: None declared, Chio Yokose: None declared, Amit Joshi: None declared, Tony Merriman: None declared, Kenneth Saag Consultant of: Arthrosi, Atom Bioscience, Horizon Therapeutics, LG Pharma, Mallinkrodt, SOBI, Takeda, Grant/research support from: Horizon Therapeutics, SOBI, Shanton, Yuqing Zhang: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, and Vaxart.

Grant/research support from: Ironwood, Horizon

Antiseizure medication treatment pathways for US Medicare beneficiaries with newly treated epilepsy

OBJECTIVE

This study was undertaken to characterize antiseizure medication (ASM) treatment pathways in Medicare beneficiaries with newly treated epilepsy.

METHODS

This was a retrospective cohort study using Medicare claims. Medicare is the United States' federal health insurance program for people aged 65 years and older plus younger people with disabilities or end-stage renal disease. We included beneficiaries with newly treated epilepsy (International Classification of Diseases codes for epilepsy/convulsions 2014-2017, no ASM in the previous 2 years). We displayed the sequence of ASM fills using sunburst plots overall, then stratified by mood disorder, age, and neurologist prescriber. We tabulated drug costs for each pathway.

RESULTS

We included 21 458 beneficiaries. Levetiracetam comprised the greatest number of pill days (56%), followed by gabapentin (11%) and valproate (8%). There were 22 288 unique treatment pathways. The most common pathways were levetiracetam monotherapy (43%), gabapentin monotherapy (10%), and valproate monotherapy (5%). Gabapentin was the most common second- and third-line ASM. Whereas only 2% of pathways involved first-line lacosamide, those pathways accounted for 19% of cost. Gabapentin and valproate use was increased and levetiracetam use was decreased in beneficiaries with mood disorders compared to beneficiaries without mood disorders. Levetiracetam use was increased and gabapentin, valproate, lamotrigine, and topiramate use was decreased in beneficiaries aged >65 years compared with those aged 65 years or less. Lamotrigine, levetiracetam, and lacosamide use was increased and gabapentin use was decreased in beneficiaries whose initial prescriber was a neurologist compared to those whose prescriber was not a neurologist.

SIGNIFICANCE

Levetiracetam monotherapy was the most common pathway, although substantial heterogeneity existed. Lacosamide accounted for a small percentage of ASMs but a disproportionately large share of cost. Neurologists were more likely to prescribe lamotrigine compared with nonneurologists, and lamotrigine was prescribed far less frequently than may be endorsed by guidelines. Future work may explore patient- and physician-driven factors underlying ASM choices.

OP0166 CHRONIC KIDNEY DISEASE AND AMPLIFICATION OF SERUM URATE IMPACT ON GOUT RISK: POPULATION-BASED STUDY OF > 450,000 UK BIOBANK PARTICIPANTS

Background

Serum urate (SU) is a necessary causal factor for development of gout, while chronic kidney disease (CKD) is associated with increased inflammatory biomarkers, cytokines, and reduced AMPK activity levels. Furthermore, CKD has been found to be associated with an increased risk of incident gout, even beyond (i.e., independent of) SU levels. As such, the impact of SU may be enhanced by presence of CKD, but this hypothesis has not been evaluated.

Objectives

To prospectively examine whether CKD modifies the relation between SU levels and risk of incident gout.

Methods

We conducted a prospective cohort analysis of UK Biobank participants with urate and creatinine levels available from baseline blood samples (2006-2010), and no prior diagnosis of gout or urate lowering therapy use. CKD Stage ≥ 3 status (eGFR <60 mL/min) was determined from latest CKD-Epi equations (NEJM 2021; JASN 2021).1,2 Incident cases of gout were ascertained from linked hospitalisation, primary care, and death records. Participants were followed from baseline up to 10 years or until gout diagnosis, death, or end of study period (Dec 31/19).

We calculated 10-year cumulative incidence of gout according to baseline SU category and CKD status and evaluated their individual and joint impact on gout risk using multivariable Cox proportional hazards models.

We further assessed for additive and multiplicative interactions3 between levels of SU and inverted eGFR, on a standardized continuous scale per SD.

Results

We included 458,244 individuals (45% male, mean age 56.5 years), of whom 6,559 had CKD at baseline, and documented 5,847 cases of incident gout over 4,442,866 person-years.

10-year cumulative incidence of gout ranged from 0.2% (baseline SU < 5 mg/dL) to 33% (baseline SU ≥ 10 mg/dL), and in each category incidence was higher for those with CKD than without (Table 1; Figure 1-left), Multivariable hazard ratio (HR) for the joint effect of CKD and highest SU level (≥ 10 mg/dL), compared to non-CKD and lowest SU (<5mg/dL), was 242 (95% CI: 189 to 309) (Figure 1-right).

Table 1.

Cumulative incidence and hazard ratio (HR) of incident gout according to baseline serum urate levels and CKD status

CKD Stage ≥ 3Hyperuricemia (Dichotomous)Serum urate, mg/dL<55.0 to < 6.06.0 to < 7.07.0 to < 8.08.0 to < 9.09.0 to < 10.0≥10<7.0≥7.0N cases6152895150104874943610-Year Cumulative Incidence0.6%1.1%1.7%7.6%19.1%28.0%42.0%1.2%16.6%Incidence Rate Ratio1.0 (Ref)1.72.712.333.856.1107.71.0 (Ref)15.2No CKDSerum urate, mg/dL<55.0 to < 6.06.0 to < 7.07.0 to < 8.08.0 to < 9.09.0 to < 10.0≥10<7.0≥7.0N cases393446105617691251363841,8953,46710-Year Cumulative Incidence,0.2%0.4%1.4%6.0%15.6%23.5%27.5%0.5%8.8%Incidence Rate Ratio1.0 (Ref)2.18.034.696.9155.9198.81.0 (Ref)20.2Joint Effect of Serum Urate and CKDSerum urate, mg/dL<55.0 to < 6.06.0 to < 7.07.0 to < 8.08.0 to < 9.09.0 to < 10.0≥10<7.0≥7.0Age-, Sex-, and Race- Adjusted HRNo CKD1.0 (Ref)1.97.029.883.0133.3170.31.0 (Ref)15.7CKD3.25.17.834.193.3155.9302.32.530.5Fully adjusted HR*No CKD1.0 (Ref)1.86.425.869.4108.7132.91.0 (Ref)12.5CKD3.14.76.828.975.2121.1241.82.322.4

*Adjusted for age, sex, race, body mass index, hypertension, diuretic use, smoking, and consumption of alcohol, coffee, meat, fish, poultry, and milk.

There was a significant additive interaction between continuous SU and eGFR (relative excess risk due to interaction=0.16 [0.09 to 0.24], p < 0.001), with HRs of 3.7 (3.6 to 3.8) per SD increase of SU, 1.2 (1.2 to 1.3) per SD increase of inverted eGFR, and 4.1 (3.9 to 4.2) for their joint effect. Their multiplicative interaction was also significant (p < 0.001).

Conclusion

These large prospective cohort data suggest CKD presence enhances the effect of elevated SU levels on risk of incident gout. They support roles of CKD-associated factors beyond SU in developing gout, such as reduced AMPK activity levels and altered inflammatory factors in CKD, which warrant further investigation.

References

[1]PMID 34554658

[2]PMID 34556489

[3]ARD (2021) PMID 34857519

Disclosure of Interests

Natalie McCormick: None declared, Leo Lu: None declared, Chio Yokose: None declared, Amit Joshi: None declared, Yuqing Zhang: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, and Vaxart., Grant/research support from: Ironwood and Horizon

POS0276 TRADITION VS INNOVATION! CONVENTIONAL RADIOGRAPHY AND ULTRASOUND IN THE DIAGNOSIS OF CPPD: INSTRUCTIONS FOR USE

Background

Conventional radiography (CR) is widely used as the first-line investigation for calcium pyrophosphate deposition (CPPD) disease, given its widespread use and the low cost. Next to it a series of advanced imaging techniques have been evaluated for accuracy and reliability. Among them, ultrasound (US) has been thoroughly tested and demonstrated to be accurate and reliable for CPPD diagnosis. However, even if there are data on the diagnostic accuracy of US and CR alone, it is not clear if performing both diagnostic tests and in which sequential order provides an added value for the diagnosis of CPPD.

Objectives

The aim of this study was to assess which diagnostic test performs better for the diagnosis of CPPD and if a combination of the two exams provides an additional value.

Methods

This is an ancillary study of the criterion validity of US in CPPD study1. Consecutive patients with knee osteoarthritis requiring total joint replacement were enrolled in 8 centres. Participants underwent US and CR of the affected knee prior to surgery. US was performed by experienced sonographers following the same scanning protocol described in the main study, while CR were performed in weight bearing AP and lateral views and were read by 2 experienced radiologists that reached a consensus on the presence/absence of CPPD. The evaluation of CPPD at the level of menisci and hyaline cartilage (HC) was based on the OMERACT definitions for US and on the new definitions developed by the ACR/EULAR CPPD classification criteria working group for CR [paper under submission]. Patients were classified as having CPPD considering histological examination as reference standard. Diagnostic indexes were calculated for US and CR alone and combined. Poisson models with robust estimation were used to estimate the best sequence of these diagnostic methods for a more accurate diagnosis of CPPD.

Results

51 pts were enrolled (63% F, mean age 74y ± 8). Diagnostic indexes of US and CR alone and combined are indicated in Table 1. Compared to histology, US demonstrated to be a sensitive tool for identification of CPPD at the knee, with a good sensitivity in all sites and in the overall evaluation. Instead, CR was less sensitive, but it was a highly specific exam for CPPD identification. Combining US and CR led to a higher sensitivity compared with CR alone, but a lower specificity compared to both CR and US alone, and it offered no additional increase in diagnostic accuracy. The Figure 1 shows the results of the appropriate sequence of use of US and CR in patients with suspected CPPD: in case of a positive CR at any of the 3 sites (menisci and HC) no additional exam is necessary, and the same in case of a positive US in at least two sites; however in case of a negative CR, US could help in a statistically significant way to identify CPPD patients, and further in case of a positive US in a single site CR can offer additional information.

Table 1.

diagnostic indexes of US, CR and US + CR in the identification of CPPD. MM: medial meniscus, LM: lateral meniscus, HC: hyaline cartilage, SN: sensitivity, SP: specificity, PPV: positive predictive value, NPV: negative predictive value, ACC: accuracy.

USSNSPPPVNPVACCMM0.880.810.820.880.84LM0.880.730.760.860.80HC0.780.860.820.830.82Overall0.920.640.730.890.78CRMM0.32110.610.67LM0.400.960.910.630.69HC0.480.930.850.680.73Overall0.540.920.880.660.73US + CRMM0.880.810.820.880.84LM0.920.690.740.900.80HC0.870.820.800.890.84Overall0.920.560.670.880.75Figure 1.

evaluation of sequence of US and CR

Conclusion

US confirmed a high diagnostic accuracy in identifying patients affected by CPPD at knee level, while CR demonstrated a high specificity but a low sensitivity. Performing both diagnostic tests could make sense in case of a negative CR or in case of an inconclusive US (only one positive site). To our knowledge, this is the first study that investigates the role of the combination of the two exams in CPPD. Further studies in a large number of patients and in different joints would be helpful to address this point.

References

[1]Filippou G. et al, Ann Rheum Dis, 2020

Disclosure of Interests

None declared

OP0164 A POPULATION-BASED, PROSPECTIVE METABOLOMICS STUDY IN THE UK BIOBANK IDENTIFIES GLYCOPROTEIN ACETYLS AS A NOVEL BIOMARKER OF INCIDENT GOUT

Background

Serum urate (SU) level is the strongest known causal predictor of clinical gout, but only ~20% with prolonged hyperuricemia develop gout, motivating the need for additional biomarkers for risk prediction and stratification. The metabolome represents a compelling intermediate trait between genome and phenome to elucidate disease mechanisms. Multiple cross-sectional studies of prevalent gout from men in Asia have been conducted, but no prospective data for incident gout (prediagnostic metabolome) are available.

Objectives

Our objectives were to (1) conduct a discovery-based metabolome-wide study to identify novel biomarkers of incident gout; and (2) replicate novel metabolomic biomarkers of gout in independent samples.

Methods

We conducted a prospective cohort analysis of 105,703 UK Biobank (UKB) participants (46% males, mean age 57.2 years) with targeted NMR metabolomic profiling (N=168 metabolites, including routine lipids and amino acids) available from baseline samples (2006-10), and no prior diagnosis of gout or urate lowering therapy use. Incident cases of gout were documented from linked medical records until gout diagnosis, death, or end of study period (Dec 31/19). We used Cox proportional hazard models to obtain hazard ratios (HR) and 95% confidence intervals (CIs) per standard deviation (SD) increase in each of the 168 metabolites to determine associations with incident gout.

To replicate our findings, we assessed association of metabolome-wide significant metabolites in a replication set, restricted to 4,804 non-overlapping participants who provided blood in the repeat assessment visit (2012-13).

Results

During a median 10.4 years follow-up, we documented 1,367 cases of incident gout in the discovery set. After correction for multiple comparisons, glycoprotein acetyls (GlycA) were positively associated with risk of incident gout (multivariable HR per 1SD increase = 1.34 (1.27 to 1.41), P = 9.04x 10-28) after adjusting for age, sex, and lifestyle and clinical covariates (Table 1). This association persisted even after SU adjustment (HR 1.07, P = 0.0091). In the replication set, among 4,804 participants followed for a median of 6.8 years, we documented 22 cases. In this dataset, we replicated GlycA association with incident gout (multivariable HR per 1SD increase =1.56 (1.08 to 2.25), P = 0.017).

Table 1.

Association of glycoprotein acetyls (GlycA) with risk of incident gout in the UK Biobank

ModelUnivariable HR, (95% CI)PMultivariable HR, (95% CI)PDiscovery (N= 105,703)Per Standard deviation:GlycA, per SD1.48 (1.41 to 1.60)3.7x10-591.34 (1.27 to 1.41)9.04x 10-28Categorized as quintiles:GlycA, Q11.0 Ref1.0 RefGlycA, Q21.43 (1.13 – 1.80)0.0021.30 (1.03 – 1.64)0.0252GlycA, Q32.06 (1.66 – 2.56)4.88 x 10-111.73 (139 – 2.15)7.64 x 10-07GlycA, Q42.53 (2.05 – 3.12)4.15 x 10-181.98 (1.60 – 2.45)3.96 x 10-10GlycA, Q53.70 (3.02 – 4.52)3.21 x 10-372.63 (2.12 – 3.23)2.01 x 10-19Replication (N= 4804)Per Standard deviation:GlycA, per SD1.65 (1.19 to 2.29)0.00271.56 (1.08 to 2.25)0.0172

1 Hazard ratios (HR) and 95% confidence intervals (CIs) obtained after adjusting for the first 4 genomic principal components (controlling for population stratification), age, sex, fasting (<4 hrs, 4-8 hrs and ≥8 hrs), smoking (never, former, current), freq of alcohol, BMI, diabetes (yes/no) and hypertension at baseline (yes/ no).

Conclusion

In this large-scale, prospective metabolomics study, we identified and independently replicated our findings that plasma levels of GlycA are associated with incident gout in UKB participants. GlycA is novel for gout, though this pro-inflammatory biomarker has predicted risk of other cardiometabolic-inflammatory phenotypes, independent of CRP.1 These findings may provide insight into the metabolic-inflammatory pathogenesis of gout, with implications for risk prediction, even beyond SU, but call for further investigation with more extensive metabolome profiling and external replication.

References

[1]Kettunen; PMID 30571186

Disclosure of Interests

Amit Joshi: None declared, Natalie McCormick: None declared, Chio Yokose: None declared, Na Lu: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, Vaxart, Grant/research support from: Ironwood, Horizon

POS1171 TRIPLE THE RATE OF EMERGENCY ROOM VISITS AND HOSPITALIZATIONS FOR GOUT AMONG US BLACKS VS WHITES – 2019 NATIONWIDE ANALYSIS

Background

Gout is a highly prevalent inflammatory arthritis with increasing global disease burden in recent years.1,2 Gout prevalence has been reported to be higher among Blacks compared to Whites,3 and that they are less likely to receive allopurinol in outpatient care.4 The potential nationwide impact of these racial disparities on emergency department (ED) visits and hospitalizations is unknown.

Objectives

To examine the contemporary racial disparities in ED visits and hospitalizations with a primary discharge diagnosis of gout in the US (2019).

Methods

We compared ED visits and hospitalizations between Blacks and Whites in the latest data (2019) from the US National Emergency Department Sample (NEDS) and National Inpatient Sample (NIS). We focused on encounters for which the primary diagnosis was gout based on ICD codes (M1A.xx, M10.xx). We calculated annual population rates of ED visits and hospitalizations for gout (per 100,000 US adults) using the 2019 US census adult population (>18 years) according to race.

Results

There were a total of 160,759 ED visits and 9,560 hospitalizations among White and Blacks with a gout diagnosis in the US in 2019. The mean age (58.2 years vs. 56.5 years) and male proportion (78.0% vs. 74.8%) tended to be higher among Whites, while more Blacks tended to live in the South (40.7% vs. 66.5%) and reported a median household income of < $50,000 (30.7% vs. 57.1%). Compared to Whites, Blacks had 2.7- and 3.2-fold higher rates of gout ED visits and hospitalizations, respectively, after adjusting for age, sex, payer, region, and household income (Table 1 & Figure 1). Black women, in particular, had 3.4- and 4.0-fold higher rates of ED visits and hospitalizations compared to White women, while the corresponding rate ratios for men were 2.5 and 2.8, respectively. The mean costs per gout ED visit were similar for Blacks compared to Whites (adjusted difference, -$7.6 [95% CI, -25.4 to 1.0]), while hospitalizations were more costly (adjusted difference, $1,055.3 [95% CI, 553.1 to 1557.5]). The duration of ED visits and hospitalizations was also higher among Blacks than Whites (adjusted difference of 0.41 days [95% CI, 0.19 to 0.63] and 0.59 days [95% CI, 0.25 to 0.94], respectively).

Table 1.

Racial Disparities in Emergency Department Visits and Hospitalizations with Primary Diagnosis of Gout in 2019

Emergency Department VisitsHospitalizationsRaceWhiteBlackWhiteBlackAll6801196524521330198510434519150Visits, N888107194962003360Rate per 100,000130.6293.431.274.4Rate Ratio (95% CI)*1.0 (ref)2.81 (2.63, 3.00)1.0 (ref)3.08 (2.79, 3.40)Rate Ratio (95% CI)**1.0 (ref)2.66 (2.50, 2.82)1.0 (ref)3.17 (2.86, 3.50)Women3785136914363031110390932647105Visits, N195671816317701145Rate per 100,00051.7126.516.043.3Rate Ratio (95% CI)*1.0 (ref)3.68 (3.39, 3.99)1.0 (ref)4.01 (3.40, 4.73)Rate Ratio (95% CI)**1.0 (ref)3.36 (3.11, 3.62)1.0 (ref)4.02 (3.39, 4.78)Men301561011015657388098151871620Visits, N692285378344302215Rate per 100,000229.6529.550.3118.3Rate Ratio (95% CI)*1.0 (ref)2.59 (2.42, 2.78)1.0 (ref)2.66 (2.36, 3.00)Rate Ratio (95% CI)**1.0 (ref)2.47 (2.32, 2.64)1.0 (ref)2.77 (2.45, 3.14)

*Adjusted for age and sex for all, adjusted for age for sex-specific rate ratios

**Adjusted for age, sex, payment, region, and household income

Conclusion

These latest national data indicate that ED visits and hospitalization due to gout are both 3 times higher among Blacks than Whites; this disparity was particularly prominent among women with gout. Higher risk of developing gout3 and suboptimal care4 both translate to these avoidable costly healthcare utilizations, calling for improved primary prevention and gout care.

References

[1]Safiri et al., PMID 32755051

[2]Xia et al., PMID 31624843

[3]Chen-Xu et al., PMID 30618180

[4]Krishnan et al., PMID 18260174

Disclosure of Interests

Chio Yokose: None declared, Natalie McCormick: None declared, Na Lu: None declared, Amit Joshi: None declared, Lesley Jackson: None declared, Minna Kohler Speakers bureau: Lilly, Consultant of: Mymee, Novartis, Grant/research support from: Setpoint Medical, Janeth Yinh: None declared, Yuqing Zhang: None declared, Kenneth Saag Consultant of: Arthrosi, Atom Bioscience, Horizon Therapeutics, LG Pharma, Mallinkrodt, SOBI, Takeda, Grant/research support from: Horizon Therapeutics, SOBI, Shanton, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, and Vaxart, Grant/research support from: Ironwood and Horizon

AB0624 Patients with vasculitis have a high prevalence of coronary microvascular dysfunction

Background

Vasculitides are a heterogenous group of diseases characterized by intense vessel wall inflammation, endothelial injury, and systemic inflammation. Several vasculitides are associated with high risk of cardiovascular (CV) disease, an important source of morbidity and mortality in this population. This excess CV risk is attributed both to a high burden of traditional risk factors and to inflammation, but this remains poorly studied. Indeed, inflammation is a known risk factor for CV disease and implicated in coronary microvascular dysfunction (CMD) which may precede obstructive coronary artery disease (CAD).

Objectives

We sought to assess whether vasculitis is associated with CMD in the absence of obstructive CAD.

Methods

We retrospectively identified subjects with systemic vasculitis who underwent symptom prompted rest/stress myocardial perfusion PET. Patients with an abnormal myocardial perfusion study (summed stress score ≥3) or LVEF<40% were excluded. Controls were identified from the same population and matched on age, gender and cardiovascular risk factors (CAD, hypertension, dyslipidemia, diabetes mellitus, and obesity). Coronary flow reserve (CFR), was calculated as the ratio of myocardial blood flow (ml/min/g) at peak stress compared to rest. CMD was defined as CFR <2.

Results

We studied 26 vasculitis cases and 66 matched controls. The most common vasculitides were giant cell arteritis (38%), ANCA-associated vasculitis (31%), and Takayasu’s arteritis (12%). Median (IQR) time between diagnosis and PET was 6.5 (2.9, 14.2) years. Seven (27%) cases had active vascultis at the time of PET. Cases and controls were well-matched on age, sex, and CV risk factors (Table 1). Despite a similar prevalence of CV risk factors, coronary flow reserve (reflected by CMD) was abnormal in 38% of vasculitis cases compared to 15% of controls (p=0.004). The mean [SD] CFR was 19% lower in vasculitis cases vs controls (2.11 [0.5] versus 2.6 [0.7], p=0.003).

Table 1.

The presence of coronary microvasculature dysfunction in patients with systemic vasculitis without obstructive coronary artery disease

Cohort characteristicsVasculitis (n=26)Control (n=66)P-valueAge at PET, years62 (18)61 (17)0.24Time from Vasculitis Diagnosis to PET, years (median, IQR)6.5 (2.9, 14.2)n/aFemale, n (%)18 (72%)43 (65%)0.99Vasculitis CharacteristicsLarge Vessel (e.g., giant cell arteritis, Takayasu’s), n(%)13 (50%)n/an/aMedium Vessel (e.g., polyarteritis nodosa, Kawasaki’s arteritis), n(%)2 (8%)n/an/aSmall Vessel (e.g., ANCA-associated vasculitis, Henoch-Schonlein Purpura), n(%)11 (42%)n/an/aCardiovascular Risk FactorsAt DiagnosisAt PETAt PETHypertension, n (%)12 (46%)20 (71%)47 (80%)0.47Obesity, n (%)3 (12%)2 (32%)2 (32%)0.84Diabetes, n (%)3 (12%)5 (20%)13 (20%)0.99Dyslipidemia, n (%)4 (15%)15 (58%)40 (61%)0.99Known CAD, n (%)0 (0%)1 (4%)1 (2%)0.48Imaging FindingsRest myocardial blood flow, ml/min/g1.0 (0.3)1.0 (0.3)0.8Stress myocardial blood flow, ml/min/g2.1 (0.6)2.6 (1.0)0.008Coronary Flow Reserve, ml/min/g*2.1 (0.5)2.6 (0.7)0.003Coronary Microvasculature Dysfunction** (CMD), n (%)10 (38%)11 (15%)0.004

Conclusion

Patients with systemic vasculitis, even in the absence of obstructive CAD, have a high prevalence of CMD compared with non-vasculitis patients. These differences were observed despite matching cases and controls on traditional CV risk factors, highlighting the importance of other factors, such as inflammation and vasculitis treatments on CMD and CV disease in this population. CMD is a known independent risk factor for CV mortality. Future prospective studies are needed to understand the relationship between vasculitis, systemic inflammation, and CMD.

Disclosure of Interests

None declared

POS0370 COMPARATIVE RETINOPATHY RISK OF HIGH- VS LOW-DOSE HYDROXYCHLOROQUINE AMONG 4,677 INCIDENT LONG-TERM USERS: EMULATED TARGET TRIAL ANALYSES

Background

Hydroxychloroquine (HCQ) is a key treatment for patients with lupus, but the major long-term toxicity is HCQ retinopathy. A large cross-sectional study found a prevalence of HCQ retinopathy of 7.5% overall and 5 times higher odds associated with HCQ dose >5 mg/kg/day, which led to ophthalmology guidelines recommending the avoidance of HCQ dosing >5 mg/kg.1 However, whether this dosing recommendation is applicable to the future risk of HCQ retinopathy is unknown, as is the incidence of severe bullseye retinopathy vs. the mild, pre-symptomatic stage. Furthermore, recent studies have indicated that the use of lower doses of HCQ may increase the risk of lupus flares and hospitalizations.2

Objectives

To determine the incidence of HCQ retinopathy associated with long-term HCQ use and compare them according to HCQ dose.

Methods

We emulated a hypothetical target trial using observational data3 from the US integrated health network Kaiser Permanente Northern California to compare two HCQ weight-based dosing strategies, >5 vs ≤5 mg/kg/day, based on dispensed tablets per year. A secondary analysis evaluated >80% of prescription days covered by dispensed tablets per year with HCQ dose >5 vs ≤5 mg/kg. We included 4,677 patients who initiated and continued HCQ for at least 5 years between 1997-2020. We emulated randomization of treatment strategy by cloning each subject and assigning a replicate to each treatment group.3 We censored replicates if and when they deviated from the assigned treatment group, assessed as the average dose in the first 5 years and annually thereafter. We used inverse probability weighting to account for censoring. The primary outcome was HCQ retinopathy, assessed by expert adjudication of spectral domain-optical coherence tomography (SD-OCT) and graded by severity. All SD-OCTs were prospectively reviewed by an expert ophthalmologist (RM), and a second expert ophthalmologist (MM) reviewed all abnormal scans and a random subset of normal scans. We assessed intra-rater reliability of SD-OCT findings. We used pooled logistic regression to estimate the cumulative incidence of HCQ retinopathy for each HCQ dose strategy from initiation. The odds ratios approximated hazard ratios (HRs) because the outcome at each one-year time block is <5%.

Results

Among 4,677 patients, the mean age at HCQ initiation was 52 years; 83% were female. The racial/ethnic composition included 51% non-Hispanic White, 19% Hispanic, 14% Asian, and 11% Black patients. 756 (16.2%) and 3,921 (83.8%) patients initiated HCQ with the primary definition of the treatment strategies >5 and ≤5 mg/kg/day, respectively. The weighted kappa was 0.80 for SD-OCT reliability. 164 patients developed HCQ retinopathy (100 mild, 38 moderate, and 26 severe cases). The cumulative incidence of retinopathy over 18 years was 37.6% for >5 and 5.7% for ≤5mg/kg of HCQ in our primary analysis. The corresponding risk was 26.5% for >5 and 3.2% for ≤5 mg/kg in our secondary analysis using >80% of prescription days. Compared with ≤5 mg/kg of HCQ, the HRs of retinopathy were 9.65 (95% CI 5.73-16.65) and 10.79 (95% CI 6.40-20.07) for >5 mg/kg using the primary and secondary definitions of HCQ dose categories, respectively (Figure 1).

Conclusion

The risk of HCQ retinopathy associated with long-term adherence to >5 mg/kg dosing was high, approximately 10 times that of ≤5 mg/kg dosing. However, most cases identified during the study were mild and pre-symptomatic, supporting the value of regular screening. These data should be incorporated into individualized decisions about long-term use of HCQ.

References

[1]Melles RB, Marmor MF. The risk of toxic retinopathy in patients on long-term hydroxychloroquine therapy. JAMA Ophthalmol 2014;132(12):1453-60

[2]Almeida-Brasil CC et al. Flares after hydroxychloroquine reduction or discontinuation: results from the SLICC inception cohort. Ann Rheum Dis 2021 Dec 15, epub ahead of print

[3]Hernán MA, Robins JM. Using Big Data to Emulate a Target Trial When a Randomized Trial Is Not Available. Am J Epidemiol 2016;183(8):758-64

Disclosure of Interests

April Jorge: None declared, Ronald Melles: None declared, Michael Marmor: None declared, Carol Conell: None declared, Baijun Zhou: None declared, Jingbo Niu: None declared, Yuqing Zhang: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, and Vaxart., Grant/research support from: Ironwood and Horizon

Patient characteristics and antiseizure medication pathways in newly diagnosed epilepsy: Feasibility and pilot results using the common data model in a single-center electronic medical record database

INTRODUCTION

Efforts to characterize variability in epilepsy treatment pathways are limited by the large number of possible antiseizure medication (ASM) regimens and sequences, heterogeneity of patients, and challenges of measuring confounding variables and outcomes across institutions. The Observational Health Data Science and Informatics (OHDSI) collaborative is an international data network representing over 1 billion patient records using common data standards. However, few studies have applied OHDSI's Common Data Model (CDM) to the population with epilepsy and none have validated relevant concepts. The goals of this study were to demonstrate the feasibility of characterizing adult patients with epilepsy and ASM treatment pathways using the CDM in an electronic health record (EHR)-derived database.

METHODS

We validated a phenotype algorithm for epilepsy in adults using the CDM in an EHR-derived database (2001-2020) against source records and a prospectively maintained database of patients with confirmed epilepsy. We obtained the frequency of all antecedent conditions and procedures for patients meeting the epilepsy phenotype criteria and characterized ASM exposure sequences over time and by age and sex.

RESULTS

The phenotype algorithm identified epilepsy with 73.0-85.0% positive predictive value and 86.3% sensitivity. Many patients had neurologic conditions and diagnoses antecedent to meeting epilepsy criteria. Levetiracetam incrementally replaced phenytoin as the most common first-line agent, but significant heterogeneity remained, particularly in second-line and subsequent agents. Drug sequences included up to 8 unique ingredients and a total of 1,235 unique pathways were observed.

CONCLUSIONS

Despite the availability of additional ASMs in the last 2 decades and accumulated guidelines and evidence, ASM use varies significantly in practice, particularly for second-line and subsequent agents. Multi-center OHDSI studies have the potential to better characterize the full extent of variability and support observational comparative effectiveness research, but additional work is needed to validate covariates and outcomes.

Clinical and EEG factors associated with antiseizure medication resistance in idiopathic generalized epilepsy

OBJECTIVE

We sought to determine which combination of clinical and electroencephalography (EEG) characteristics differentiate between an antiseizure medication (ASM)-resistant vs ASM-responsive outcome for patients with idiopathic generalized epilepsy (IGE).

METHODS

This was a case-control study of ASM-resistant cases and ASM-responsive controls with IGE treated at five epilepsy centers in the United States and Australia between 2002 and 2018. We recorded clinical characteristics and findings from the first available EEG study for each patient. We then compared characteristics of cases vs controls using multivariable logistic regression to develop a predictive model of ASM-resistant IGE.

RESULTS

We identified 118 ASM-resistant cases and 114 ASM-responsive controls with IGE. First, we confirmed our recent finding that catamenial epilepsy is associated with ASM-resistant IGE (odds ratio [OR] 3.53, 95% confidence interval [CI] 1.32-10.41, for all study subjects) after covariate adjustment. Other independent factors seen with ASM resistance include certain seizure-type combinations (absence, myoclonic, and generalized tonic-clonic seizures [OR 7.06, 95% CI 2.55-20.96]; absence and generalized tonic-clonic seizures [OR 4.45, 95% CI 1.84-11.34]), as well as EEG markers of increased generalized spike-wave discharges (GSWs) in sleep (OR 3.43, 95% CI 1.12-11.36 for frequent and OR 7.21, 95% CI 1.50-54.07 for abundant discharges in sleep) and the presence of generalized polyspike trains (GPTs; OR 5.49, 95% CI 1.27-38.69). The discriminative ability of our final multivariable model, as measured by area under the receiver-operating characteristic curve, was 0.80.

SIGNIFICANCE

Multiple clinical and EEG characteristics independently predict ASM resistance in IGE. To improve understanding of a patient's prognosis, clinicians could consider asking about specific seizure-type combinations and track whether they experience catamenial epilepsy. Obtaining prolonged EEG studies to record the burden of GSWs in sleep and assessing for the presence of GPTs may provide additional predictive value.

Impact of COVID-19 on TB epidemiology in South Korea

SETTING: Five referral hospitals, South Korea.OBJECTIVE: To assess epidemiological changes in TB before and during the COVID-19 pandemic.DESIGN: This was a multicentre cohort study of 3,969 patients diagnosed with TB.RESULTS: We analysed 3,453 patients diagnosed with TB prior to the COVID-19 pandemic (January 2016-February 2020) and 516 during the pandemic (March-November 2020). During the pandemic, the number of patients visits declined by 15% from the previous 4-year average, and the number of patients diagnosed with TB decreased by 17%. Patients diagnosed during the pandemic were older than those diagnosed before the pandemic (mean age, 60.2 vs. 56.6 years, P < 0.001). The proportion of patients to have primary TB at a younger age (births after 1980) among those diagnosed with TB was significantly lower during the pandemic than before (17.8% in 2020 vs. 23.5% in 2016, 24.0% in 2017, 22.5% in 2018, 23.5% in 2019; P = 0.005).CONCLUSIONS: The COVID-19 pandemic resulted in a reduction in the number of visits to respiratory departments, leading to fewer patients being diagnosed with TB. However, our results suggest that universal personal preventive measures help to suppress TB transmission in regions with intermediate TB burden.

Inverse Laplace transformation analysis of stretched exponential relaxation

We investigate the effectiveness of the Inverse Laplace Transform (ILT) analysis method to extract the distribution of relaxation rates from nuclear magnetic resonance data with stretched exponential relaxation. Stretched-relaxation is a hallmark of a distribution of relaxation rates, and an analytical expression exists for this distribution for the case of a spin-1/2 nucleus. We compare this theoretical distribution with those extracted via the ILT method for several values of the stretching exponent and at different levels of experimental noise. The ILT accurately captures the distributions for β≲0.7, and for signal to noise ratios greater than ∼40; however the ILT distributions tend to introduce artificial oscillatory components. We further use the ILT approach to analyze stretched relaxation for spin I>1/2 and find that the distributions are accurately captured by the theoretical expression for I=1/2. Our results provide a solid foundation to interpret distributions of relaxation rates for general spin I in terms of stretched exponential fits.

Genomic analysis of "microphenotypes" in epilepsy

Large international consortia examining the genomic architecture of the epilepsies focus on large diagnostic subgroupings such as "all focal epilepsy" and "all genetic generalized epilepsy". In addition, phenotypic data are generally entered into these large discovery databases in a unidirectional manner at one point in time only. However, there are many smaller phenotypic subgroupings in epilepsy, many of which may have unique genomic risk factors. Such a subgrouping or "microphenotype" may be defined as an uncommon or rare phenotype that is well recognized by epileptologists and the epilepsy community, and which may or may not be formally recognized within the International League Against Epilepsy classification system. Here we examine the genetic structure of a number of such microphenotypes and report in particular on two interesting clinical phenotypes, Jeavons syndrome and pediatric status epilepticus. Although no single gene reached exome-wide statistical significance to be associated with any of the diagnostic categories, we observe enrichment of rare damaging variants in established epilepsy genes among Landau-Kleffner patients (GRIN2A) and pediatric status epilepticus patients (MECP2, SCN1A, SCN2A, SCN8A).