71 The Use of Sternocleidomastoid Rotational and Cervicofacial Advancement Flap for Closure of a Persistent Mastoid Cutaneous Fistula

Introduction

Postauricular mastoid fistula is a rare occurrence, typically following repeated soft tissue injury, commonly caused by chronic suppurative otitis media and repeated surgical treatments. Management is challenging with a limited number of reported, successful surgical techniques, which often have limited applicability.

Case report

We present a case of a 55-year-old male patient with a persistent right post-auricular cutaneous mastoid fistula as a result of two previous mastoidectomies. Although the patient underwent two simple primary closures, the fistula recurred. This was successfully treated with a new technique utilising a Sternocleidomastoid Rotational and Cervicofascial Advancement Flap which was completely healed at the 1-year follow-up without a recurrence of the fistula.

Conclusions

This novel technique provided a definitive obliteration of a persistent cutaneous mastoid fistula. By utilising a double layered flap, via a facelift incision, the flap results in an excellent functional and cosmetic result.

70 Availability of Personal Protective Equipment in NHS Hospitals During COVID-19: A National Survey

Introduction

The continuous supply of personal protective equipment (PPE) in the National Health Service (NHS) is paramount in order to sustain a safe level of staffing and to reduce transmission of COVID-19 to patients, public and staff.

Method

A 16-question survey was created to assess the availability and personal thoughts of healthcare professionals regarding PPE supply in England. The survey was distributed via social media (Facebook © and Twitter ©) to all UK COVID-19 healthcare professional groups, with responses collected over 3 weeks in March 2020 during the beginning of the pandemic.

Results

A total of 121 responses from physicians in 35 different hospitals were collected (105 inpatient wards, 16 from intensive care units). In inpatient wards, eye and face protection were unavailable to 19.1% of respondents. Masks were available to 97.7% of respondents and gloves in all respondents (100%). Body protection was available primarily as a plastic apron (83.8%). All of respondents working in intensive care had access to full-body PPE, except FFP3 respirator masks (available in 87.5%). PPE is ‘Always’ available for 29.8% of all respondents, and ‘Never’ or ‘Almost Never’ in 11.6%. There was a statistically significant difference between London and non-London responders that ‘Always’ had PPE available (43.9% versus 19.0%, p = 0.003).

Conclusions

This is the first survey to evaluate PPE supply in England during the COVID-19 pandemic. Our survey demonstrated an overall lack of PPE volume supply in the UK, with preferential distribution in London. Eye and full body protection are in most lack of supply.

Observational study to compare the effect of altitude on cardiopulmonary reserves of different individuals staying more than 6 weeks at 10,000 ft and 15,000 ft

Background

The variation in heights beyond high altitude has different effects on the cardiorespiratory profile of individuals because of variation in oxygen density with every thousand feet. This study was planned to analyze and compare the effects of difference in altitudes on cardiorespiratory profile from anesthesiologist's point of view.

Methods

A multicenter observational study was done involving two different groups of 600 patients at 10,000 ft (Group A) and 15,000 ft (Group B). Observation and comparison of oxygen saturation, 6-min walk test, and breath holding time was carried out.

Results

Fifty-five percent of subjects in Group A had oxygen saturation of more than 93% in comparison to 5.5% in Group B. This was statistically significant (P < 0.001). Two percent of subjects in Group A in comparison to 63.5% of Group B had oxygen saturation of less than 88% (P < 0.001). Percentage increase of more than 15% of heart rate was found to be statistically significant in all the age groups. Overall, 3.8% of individuals in Group A had breath holding time less than 15 s in comparison to 16.6% of individuals in Group B (P value < 0.001).

Conclusion

The study demonstrates that there is a significant fall in oxygen saturation, significant rise in the heart rate in 6-min walk test, and significant fall in the breath holding time in the group located at 15,000 ft. Heights beyond 10,000 ft should be restricted to life and limb saving surgeries, and logistics should be focused more on "scoop and run" than "stay and play" policy.

In silico modelling of the corrosion of biodegradable magnesium-based biomaterials: modelling approaches, validation and future perspectives

Metallic biomedical implants based on magnesium, zinc and iron alloys have emerged as bioresorbable alternatives to permanent orthopaedic implants over the last two decades. The corrosion rate of biodegradable metals plays a critical role in controlling the compatibility and functionality of the device in vivo. The broader adoption of biodegradable metals in orthopaedic applications depends on developing in vitro methods that accurately predict the biodegradation behaviour in vivo. However, the physiological environment is a highly complex corrosion environment to replicate in the laboratory, making the in vitro-to-in vivo translation of results very challenging. Accordingly, the results from in vitro corrosion tests fail to provide a complete schema of the biodegradation behaviour of the metal in vivo. In silico approach based on computer simulations aim to bridge the observed differences between experiments performed in vitro and vivo. A critical review of the state-of-the-art of computational modelling techniques for predicting the corrosion behaviour of magnesium alloy as a biodegradable metal is presented.

Near-Miss Incidents in Obstetric Patients Admitted to an Intensive Care Unit of a Tertiary Care Center in Eastern India: A Retrospective Cohort Study

Aim

Obstetric patients presenting to the intensive care units (ICU) with or without underlying medical or surgical comorbidities can be a challenge to both the treating obstetrician and the intensivist. They occasionally present with near-miss events which if left untreated, can result in death.

Objectives

To study the prevalence, indications of ICU admissions, near-miss events, and their effect on mortality in obstetric and puerperal patients.

Material & methods

We conducted a retrospective analysis of the health records of all the obstetric and puerperal patients (pregnant and until 6 weeks postpartum) admitted to our tertiary care hospital from January 2019 to December 2020. Patient demographic characteristics, obstetric, surgical, and medical conditions, acute physiology, and chronic health evaluation (APACHE) II scores, organ failures, treatment, ICU and hospital length of stay, and mortality outcomes were studied.

Results

A total of 22 obstetric patients were admitted to the ICU during the above study period. Mean age was 28.7 ± 6.24 years, mean gestation was 34.4 ± 6.61 weeks, mean APACHE II score was 12.68 ± 5.67, median ICU length of stay was 5 days, and median duration of hospital length of stay was 10 days. The antepartum risk factors such as severe preeclampsia (27%), antepartum bleeding (14%), and postpartum complications like postpartum haemorrhage (33%), sepsis with multiorgan failure (25%) are the commonest indications that resulted in ICU admission.

Conclusion

Higher APACHE II scores at the time of ICU admission, prolonged ICU, and hospital length of stay may be associated with high maternal mortality.

Intracerebral schwannoma of the angular gyrus: case report

We report an intracerebral schwannoma originating in the angular gyrus of a 20-year-old female that was incidentally diagnosed after she presented with a post-traumatic seizure. After comprehensive investigations, including functional magnetic resonance imaging, she underwent a computed tomography-guided stereotactic resection of the lesion. Pathological examination confirmed features of a schwannoma. After six years of follow-up, she remains well, without any evidence of recurrence. Intracerebral schwannomas are extremely uncommon: fewer than 90 cases have been reported. We present a comprehensive summary of the literature and a discussion of novel theories on the pathogenesis of intracerebral schwannomas.

The Use of Electrical Nerve Stimulation to Treat Migraines: A Systematic Review

Migraines have been defined as an intense unilateral throbbing or pulsating sensation lasting anywhere between a few hours to multiple days. They are the sixth most prevalent disease in the United States, with approximately 18% of women and 6% of men experiencing some form of a migraine throughout their lifetime. In addition, they pose a significant economic burden, accounting for anywhere between $13 and $17 billion in medical costs annually in the United States. While there are a wide variety of treatments for migraines on the market, such as nonsteroidal anti-inflammatory drugs (NSAIDS), beta-blockers, and anti-epileptics, there is still no standard treatment. Moreover, each of these medications has a wide range of side effects, ranging from stomach ulcers to light-headedness. Within the last few decades, the presence of electrical nerve stimulation has emerged as a possible treatment option. These methods are almost free of harmful side effects and may be able to reduce the economic burden on those who suffer from migraines. However, studies have shown mixed results in regard to their efficacy. In this paper, we performed a systematic review to detail the current state of the literature regarding electrical nerve stimulation as a treatment modality for migraines.

Complementary and Alternative Medicine Use in First-time and Recurrent Kidney Stone Formers

OBJECTIVE

To describe the patterns of complementary and alternative medicine (CAM) among patients with kidney stones and analyze the alkali content of commonly used CAM therapies.

METHODS

We prospectively conducted structured interviews with patients who presented to a specialty stone clinic for the management of kidney stones. Open-ended questions were used to elicit information regarding CAM knowledge, formulation/dosing, and patterns of use. Several common CAM therapies were then analyzed for their alkali, organic anion, and sugar content.

RESULTS

Of 103 subjects, 82 (80%) patients reported knowledge of CAM and 52 (50%) reported using CAM. Patients with recurrent kidney stones were more likely to report using CAM than patients with first-time episodes (56% vs 26%, P = 0.04). Some respondents reported their condition decreased in severity or frequency since starting CAM therapy (17%) and improvements in pain (12%). Total alkali content per serving of the tested supplements was 0 mEq (Stonebreaker), 1.5 mEq (Ocean Spray Cranberry Juice Cocktail), 4.7 mEq (Lakewood Pure Cranberry Juice), 0.6 mEq (Braggs Apple Cider Vinegar), 11.9 mEq (LithoBalance), 9.5 mEq (Simply Grapefruit Juice), 19.8 mEq (KSP-Key Lime), and 20.2 mEq (KSP-Very Berry).

CONCLUSION

Patients with kidney stones may use CAM to alleviate symptoms or prevent recurrence. Commercially available CAM therapies may contain comparable alkali content to commonly prescribed citrate therapy. These data suggest that providers should be prepared to discuss the role of CAM with their patients.

Habitual Exposure to Trigeminal Stimuli and Its Effects on the Processing of Chemosensory Stimuli

Our objective was to compare brain responses to trigeminal and olfactory stimuli in frequent and non-frequent gum chewers in order to explore whether habitual exposure to trigeminal stimuli affects their central-nervous processing. In healthy subjects, fMRI brain scans were obtained for 20 frequent gum chewers (GC) and 20 non-frequent gum chewers (N'GC), in response to four odorous stimuli; 2 'trigeminal' (peppermint and spearmint) and 2 non-trigeminal or 'olfactory' (cherry and strawberry). During measurements, subjects reported intensity and pleasantness ratings for all stimuli. In addition, a test for general trigeminal sensitivity test (lateralization test) and an odor threshold test was performed. Brain activations in response to individual odors were investigated for the total study population followed by group wise (GC and N'GC) analysis separately for responses to trigeminal (peppermint + spearmint) and olfactory (cherry + strawberry) odors. (1) The GC group exhibited higher trigeminal sensitivity compared to the N'GC group. (2) Olfactory odors activated bilateral insular cortex and amygdala. Apart from olfactory areas (amygdala, insular cortex), trigeminal odors also produced activations in right thalamus and right substantia nigra. (3) In the GC group, olfactory odors produced higher bilateral insular cortex activation than in N'GC group, but no such differences were observed for trigeminal odors. GC subjects appeared to be more responsive to trigeminal chemosensory stimuli. However, this did not directly translate into differences in central-nervous activations to trigeminal stimuli; instead, the use of chewing gum was associated with stronger brain activation towards olfactory stimuli.

A single-center experience in use of tocilizumab in COVID-19 pneumonia in India

BACKGROUND

IL-6 receptor antagonist tocilizumab (TCZ) has been used in several reported studies in the treatment of COVID-19 pneumonia and pieces of evidence are still emerging.

METHODS

All patients with COVID-19 pneumonia showing features of hyperinflammatory syndrome receiving TCZ at a tertiary care center in India were included in the study and a retrospective descriptive analysis was done.

RESULTS

Between May 2020 to August 2020, 21 patients received TCZ out of which 13 survived and 8 died. All non-survivors had longer duration (median 12 days, minimum 9, maximum 15 days compared to median 6 days, minimum 3 and maximum 14 days in survivors) of symptoms and severe disease requiring mechanical ventilation at the time of TCZ administration. Among survivors, 8 patients had severe disease, 3 had moderate disease, and 2 patients had mild disease. Six out of 8 (75%) among non-survivors and 8 out of 13 (62%) among survivors had preexisting medical comorbidities. The non-survivors had higher baseline neutrophil-to-leukocyte ratio (10.5 vs 8.8), serum ferritin (960 ng/ml vs 611 ng/ml), lactate dehydrogenase (795 IU/L vs 954 IU/L), and D-dimer (5900 μg/ml vs 1485 mg/ml) levels. No drug-related serious adverse effect was noted among the patients.

CONCLUSION

In a scenario of emerging evidence for the role of TCZ in the management of severe COVID-19, our study provides useful data on its use in the Indian scenario. Deliberate patient selection and timing initiation of TCZ at a crucial stage of the disease may be beneficial in COVID-19 pneumonia with good safety returns.

OP0005 DIETARY HYPERINSULINEMIC POTENTIAL AND RISK OF INCIDENT GOUT: 3 PROSPECTIVE COHORT STUDIES OF US MEN AND WOMEN

Background:

Gout and the metabolic (insulin resistance) syndrome frequently coexist. Intravenous insulin has been shown to raise serum urate (SU) levels in physiologic studies and a Mendelian Randomization study also showed a causal role of insulin on the risk of gout. However, it is unknown whether habitual hyperinsulinemic dietary intake confers gout risk.

Objectives:

Prospectively examine the relation between two distinct insulin-related dietary indices and risk of incident gout in three large cohorts of US women and men over 30 years.

Methods:

We studied 164,090 women from Nurses Health Study I (1986-2016) and II (1989-2017) and 40,598 men from Health Professionals Follow-up Study (1986-2016), who were free of gout at baseline. Dietary intake and covariates were assessed by validated questionnaires every 4 years. Insulinemic potential of diet was evaluated using 1) food-based empirical dietary index for hyperinsulinemia (EDIH) score that was pre-defined based on circulating C-peptide levels1 and reflects insulin resistance;2 and 2) dietary insulin index (DII), which reflects transient, postprandial insulin secretion.2 We assigned EDIH and DII scores for each participant, adjusted for total energy intake, and prospectively examined the association between scores and incident gout (using ACR survey criteria for gout3), adjusting for potential confounders.

Results:

We ascertained 2,874 incident gout cases over 5,124,490 person-years of follow-up. In pooled multivariable-adjusted analyses, those in the highest EDIH quintile had 1.76-times (95% CI: 1.56 to 1.99) higher gout risk, compared with the lowest (Table 1). This attenuated with further adjustment for BMI (a likely causal intermediate) but remained positive (RR 1.30, 1.15 to 1.48). DII scores were inversely associated with gout risk (RR 0.66, 0.58 to 0.74) (Table 1).

Table 1.

Risk Ratio (95% CI) of Gout According to Quintiles of Insulin-Related Dietary Index

EDIH (measure of insulin resistance)Q1:lowest circulating insulin levelsQ2Q3Q4Q5:highest circulating insulin levelsP for trendN cases430482598631733Person-years1,025,1291,025,2851,025,5741,025,3011,023,651Age-adjusted RR1.00 (Ref)1.13 (1.00-1.29)1.43 (1.26-1.61)1.53 (1.36-1.73)1.85 (1.64-2.09)<.0001MV-Adjusted*RR1.00 (Ref)1.11 (0.98-1.27)1.39 (1.22-1.57)1.47 (1.30-1.67)1.76 (1.56-1.99)<.0001MV-Adjusted**RR (+ BMI)1.00 (Ref)1.03 (0.90-1.17)1.21 (1.06-1.37)1.21 (1.07-1.37)1.30 (1.15-1.48)<.0001Dietary Insulin Index (measure of transient, post-prandial secretion and sensitivity)Q1:lowest insulin sensitivityQ2Q3Q4Q5:greatest insulin sensitivityP for trendN cases783611527498455Person-years1,024,7631,025,7301,025,0751,025,5381,023,834Age-adjusted RR1.00 (Ref)0.79 (0.71-0.88)0.69 (0.62-0.77)0.65 (0.58-0.73)0.59 (0.53-0.66)<.0001MV-Adjusted*RR1.00 (Ref)0.79 (0.71-0.88)0.69 (0.62-0.77)0.66 (0.59-0.74)0.60 (0.53-0.67)<.0001MV-Adjusted**RR (+ BMI)1.00 (Ref)0.78 (0.70-0.87)0.69 (0.62-0.77)0.67 (0.60-0.75)0.66 (0.58-0.74)<.0001

*Multivariable (MV) models adjusted for age (month), White race, smoking, menopause (women only), hormone use (women only), physical activity, history of hypertension, and diuretic use **MV + BMI models further adjusted for BMI (a likely causal intermediate)

Conclusion:

EDIH scores, reflecting chronic hyperinsulinemia (i.e., greater insulin resistance with reduced clearance), were positively associated with the risk of incident gout, even beyond the pathway through adiposity. Conversely, higher DII scores, which reflect short-term, postprandial elevations in insulin levels (and also greater insulin clearance and sensitivity) conferred a lower risk. This corroborates human physiologic experiments and Mendelian Randomization studies showing insulin resistance can increase SU levels by decreasing renal excretion of urate, and supports lowering insulinemic potential of diet as a strategy to reduce gout risk.

References:

[1]Tabung et al. PMID 27821188

[2]Lee et al. PMID 32618519

[3]Wallace et al. PMID 856219

Disclosure of Interests:

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

OP0202 DOES EXCESS WEIGHT AFFECT GOUT RISK DIFFERENTLY AMONG GENETICALLY PREDISPOSED INDIVIDUALS? – SEX-SPECIFIC PROSPECTIVE COHORT FINDINGS OVER >26 YEARS

Background:

Global burden of gout has increased substantially, particularly among women.1,2 Addressing obesity, a major modifiable risk factor for gout, may alleviate this burden; however, there is also a significant genetic contribution to gout risk according to the genome-wide association studies (GWAS).3,4 Genetic predisposition may modify the excess weight effect on gout risk.

Objectives:

To investigate the potential role of genetic predisposition on the association between excess weight (i.e., BMI ≥ 25 kg/m2) and gout risk in two US prospective longitudinal cohorts over >26 years, stratified by sex.

Methods:

We examined the association between excess weight and risk of incident gout meeting the ACR survey criteria,5 according to genetic risk, in 18,512 women from the Nurses’ Health Study (NHS) over 32 years, and 10,917 men from Health Professionals Follow-Up Study (HPFS) over 26 years. We derived a genetic risk score (GRS) using 114 serum urate single nucleotide polymorphisms from the latest GWAS.3 We also calculated the population attributable risk (PAR) for excess weight according to GRS stratum.

Results:

We ascertained 530 incident gout cases in NHS and 983 in HPFS. While the relative risks (RRs) due to excess weight (overweight or obesity) appeared larger among women above the mean than below the mean, the RRs among men appeared similar according to genetic predisposition (Table 1). The RRs among women for excess weight compared to normal were 1.66 (95% CI, 1.17 to 2.37) and 2.55 (1.95 to 3.34) below and above the mean GRS, respectively (P for multiplicative interaction = 0.06), whereas corresponding RRs among men were 1.68 (95% CI, 1.31 to 2.16) and 1.76 (1.47 to 2.10) (P for multiplicative interaction = 0.8). The risk differences (RD) among women for excess weight were 0.69 and 2.38 with GRS below and above the mean, respectively, resulting in the relative excess risk due to interaction (RERI) of 1.69 (95% CI, 1.03 to 2.35, P for additive interaction = 5.4x10-7); for men, the corresponding RDs were 0.70 and 1.46, with RERI = 0.76 (0.26, 1.25; P for additive interaction = 2.6x10-3). Excess weight accounted for a larger proportion of incident gout cases among women with GRS above the mean (PAR, 48.5% [95% CI, 38.8 to 55.9]) compared to those with GRS below the mean (PAR, 29.0% [95% CI, 10.5 to 42.1]), whereas the PARs among men were similar (31.6% vs 29.7%, respectively).

Table 1.

Relative Risk of Gout by Body Mass Index, Stratified by Mean Genetic Score

HPFS (men)Below MeanAbove MeanBMIOverall<2525-30>30Overall<2525-30>30No. Cases3338817273650172349129Person-Years10405543314492531148898634419944609610544Age-Adjusted RR-1.0 (ref)1.71 (1.32, 2.22)3.00 (2.18, 4.12)-1.0 (ref)1.80 (1.50, 2.16)2.87 (2.27, 3.62)MV Adjusted* RR-1.0 (ref)1.53 (1.18, 1.99)2.31 (1.66, 2.21)-1.0 (ref)1.63 (1.35, 1.96)2.38 (1.87, 3.03)NHS (women)Below MeanAbove MeanBMIOverall<2525-30>30Overall<2525-30>30No. Cases17347408635772120165Person-Years24439212384976414441292392591202297612342907Age-Adjusted RR-1.0 (ref)1.23 (0.81, 1.88)4.46 (3.10, 6.41)-1.0 (ref)2.41 (1.79, 3.23)5.68 (4.82, 7.52)MV Adjusted* RR-1.0 (ref)1.00 (0.65, 1.53)2.84 (1.92, 4.20)-1.0 (ref)1.97 (1.46, 2.65)3.61 (2.68, 4.87)

*Adjusted for age (continuous), menopause, use of hormone therapy (never, past or current), history of hypertension, and systolic and diastolic blood pressure, alcohol, total energy intake and intake of meat, seafood and dairy foods (all continuous).

Conclusion:

These large scale longitudinal prospective cohorts suggest maintaining healthy weight is an important gout prevention strategy, regardless of underlying genetic risk. In genetically predisposed individuals, addressing excess weight may prevent a large proportion of gout cases, especially among women.

References:

[1]Safiri et al., PMID 32755051

[2]Xia et al., PMID 31624843

[3]Tin et al., PMID 31578528

[4]Tai et al., PMID: 32017447

[5]Wallace et al., PMID: 856219

Acknowledgements:

The authors thank the participants of the NHS and HPFS.

CY is supported by the Rheumatology Research Foundation Scientist Development Award and NIH T32 AR007258. HC is supported by NIH P50AR060772 and R01AR065944.

Disclosure of Interests:

None declared

OP0235 PRO-INFLAMMATORY DIET AND RISK OF INCIDENT GOUT: 3 PROSPECTIVE COHORT STUDIES OF US MEN AND WOMEN

Background:

Emerging evidence suggests inflammation may drive progression from hyperuricemia to clinical gout, but the role of extrinsic, modifiable sources of chronic inflammation, such as diet, on gout risk is unknown. Notably, greater dietary inflammatory potential has been independently associated with increased risk of incident cardiovascular disease (CVD)1 and type 2 diabetes (T2D).2

Objectives:

Prospectively examine the relation between dietary inflammatory potential and risk of gout in three large cohorts of US women and men over 30 years.

Methods:

Ascertaining the ACR survey criteria for gout for several decades,3 we studied gout risk among 164,090 women from Nurses Health Study I (1986-2016) and II (1989-2017) and 40,598 men from Health Professionals Follow-up Study (1986-2016), free of gout at baseline. Dietary intake and covariates were assessed by validated questionnaires every 4 years. Inflammatory potential of diet was evaluated using a food-based empirical dietary index of inflammatory potential score (EDIP) pre-defined based on circulating levels of IL-6, C-reactive protein, adiponectin, and TNFαR2.4

We assigned an EDIP score for each participant, adjusted for total energy take, and prospectively examined the association between quintiles of EDIP score and incident gout, adjusting for potential confounders. We also stratified by alcohol intake, as alcohol has anti-inflammatory properties,4 but is associated with a higher gout risk, particularly beer.5

Results:

We documented 2,874 incident gout cases over 5,124,940 person-years of follow-up. In pooled multivariable-adjusted analyses, those in the highest EDIP quintile had 59% higher gout risk (multivariable RR 1.59; 95% CI 1.41–1.79), compared with the lowest (Table 1). This remained positive with further adjustment for BMI, a likely causal intermediate (RR 1.27, 1.12 to 1.42), and was stronger among non-drinkers (RR 2.37, 1.58 to 2.56) than drinkers (RR 1.57, 1.38 to 1.78) (Table 1).

Table 1.

Risk Ratio (95% CI) of Gout According to Quintiles of Inflammatory Diet Score, Overall and by Alcohol Use

Q1:lowestQ2Q3Q4Q5:highestP for trendOverallN cases473493530623755Person-years1,024,5711,025,6181,025,2841,024,7791,024,688Age-adjusted RR1.00 (Ref)1.05 (0.92, 1.19)1.13 (0.99, 1.27)1.33 (1.18, 1.50)1.64 (1.46, 1.84)<0.001MV-Adjusted* RR1.00 (Ref)1.04 (0.92, 1.18)1.12 (0.98, 1.26)1.31 (1.16, 1.48)1.59 (1.41, 1.79)<0.001MV-Adjusted** RR (+ BMI)1.00 (Ref)1.00 (0.88, 1.13)1.03 (0.91, 1.17)1.16 (1.02, 1.31)1.27 (1.12, 1.42)<0.001No Alcohol UseN cases265884143251Person-years118,301189,938249,389313,511396,080MV-Adjusted* RR1.00 (Ref)1.31 (0.82, 2.08)1.37 (0.88, 2.13)1.80 (1.18, 2.74)2.37 (1.58, 2.56)<0.001MV-Adjusted**RR (+ BMI)1.00 (Ref)1.28 (0.80, 2.03)1.32 (0.85, 2.05)1.61 (1.06, 2.45)1.85 (1.23, 2.79)<0.001Alcohol UseN cases447435446480504Person-years906,271835,680775,895711,267628,609MV-Adjusted* RR1.00 (Ref)1.04 (0.91, 1.19)1.13 (0.99, 1.29)1.31 (1.15, 1.50)1.57 (1.38, 1.78)<0.001MV-Adjusted** RR (+ BMI)1.00 (Ref)1.00 (0.88, 1.14)1.05 (0.92, 1.20)1.17 (1.03, 1.33)1.28 (1.12, 1.46)<0.001

*Multivariable (MV) models adjusted for age (month), White race, smoking, menopause (women only), hormone use (women only), physical activity, history of hypertension, and diuretic use. **MV + BMI models additionally adjusted for BMI (a likely causal intermediate)

Conclusion:

Habitual pro-inflammatory dietary pattern was independently associated with higher risk of incident gout in these prospective cohorts, even beyond the pathway through adiposity. Our findings support a role for chronic inflammation in development of gout, similar to CVD1 and T2D.2 Adhering to a diet with lower inflammatory potential may modulate systemic inflammation, potentially reducing gout risk and these life-threatening comorbidities.

References:

[1]Li et al. J Amer Coll Cardiology (2020) PMID 33153576

[2]Lee et al. Diabetes Care (2020) PMID 32873589

[3]Wallace et al. PMID 856219

[4]Tabung et al. PMID 27358416

[5]Choi et al. PMID 15094272

Disclosure of Interests:

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

Liver-Specific Nonviral Gene Delivery of Fibroblast Growth Factor 21 Protein Expression in Mice Regulates Body Mass and White/Brown Fat Respiration

Viral-mediated in vivo gene delivery methods currently dominate among therapeutic strategies within the clinical and experimental settings, albeit with well documented limitations arising from immunologic constraints. In this study, we demonstrate the utility of nonviral hepatotropic in vivo gene delivery of unpackaged expression constructs, including one encoding fibroblast growth factor 21 (FGF21). FGF21 is an important hepatokine whose expression positively correlates with therapeutic outcomes across various animal models of obesity. Our data demonstrate that FGF21 expression can be restored into the livers of immunocompetent FGF21 knockout mice for at least 2 weeks after a single injection with an FGF21 expression plasmid. In wild-type C57BL6/J mice, in vivo transfection with an FGF21-expressing plasmid induced weight loss, decreased adiposity, and activated thermogenesis in white fat within 2 weeks. Furthermore, in vivo FGF21 gene delivery protected C57BL6/J mice against diet-induced obesity by decreasing adiposity and increasing uncoupling protein 1-dependent thermogenesis in brown fat and by boosting respiratory capacity in subcutaneous and perigonadal white fat. Together, the data illustrate a facile and effective methodology for delivering prolonged protein expression specifically to the liver. We contend that this method will find utility in basic science research as a practical means to enhance in vivo studies characterizing liver protein function. We further believe our data provide a rationale for further exploring the potential clinical utility of nonviral gene therapy in mouse models of disease. SIGNIFICANCE STATEMENT: This study presents a valuable method for nonviral gene delivery in mice that improves upon existing techniques. The data provide a rationale for further exploring the potential clinical utility of nonviral gene therapy in mouse models of disease and will likely enhance in vivo studies characterizing liver protein function.

OP0203 GENE-DIET INTERACTION ON THE RISK OF INCIDENT GOUT AMONG WOMEN – PROSPECTIVE COHORT STUDY OVER 32 YEARS

Background:

Although gout is conventionally known as a male condition, the recent Global Burden of Disease (GBD) Study found disproportionate worsening among women.1 We have found Dietary Approaches to Stop Hypertension (DASH) diet is independently associated with a lower risk of incident gout, while Western diet is associated with increased risk.2 Whether these risks vary according to genetic risk remains unknown.

Objectives:

To investigate the influence of genetic predisposition on the relation between diets (one protective and another hazardous) and gout risk in a large prospective US cohort of women over 32 years.

Methods:

We examined the role of genes on the association between two dietary patterns (DASH and Western) on the risk of incident gout in 18,512 women from the Nurses’ Health Study. Using validated food frequency questionnaires, for each participant we derived: 1) DASH score emphasizing fruits, vegetables, nuts, legumes, whole grains, low-fat dairy, and reduced intake of saturated fat and sugar-sweetened beverages (SSBs) and 2) Western diet score characterized by high intake of red and processed meats, SSBs, desserts, French fries, and refined grains. A genetic risk score (GRS) was derived using 114 serum urate single nucleotide polymorphisms from the latest GWAS consortium.3

Results:

There were 523 incident gout cases meeting ACR survey criteria4 (170 vs. 353 in GRS below and above the mean, respectively) (Table 1). Among women with GRS below and above the mean, the multivariable relative risks (RRs) of gout were 1.0, 1.56. 1.32, 0.89, and 0.61 (0.34 to 1.09) and 1.0, 1.0, 0.85, 0.51, and 0.68 (0.49 to 0.96), for quintiles (Q) 1 through 5 of DASH score, respectively (p for interaction = 0.69) (Table 1). For the Western diet, RRs for Q1 through 5 were 1, 1.34, 1.07, 1.33, and 1.63 (0.91 to 2.93) for those with GRS below the mean and 1.0, 1.17, 0.93, 1.27, and 1.77 (1.19 to 2.61) among those with GRS above the mean, respectively (p for multiplicative interaction = 0.64).

Table 1.

Relative Risk of Gout by Quintiles of DASH and Western Diet Score, Stratified by Mean GRS

DASHBelow MeanAbove MeanQ1Q2Q3Q4Q5Q1Q2Q3Q4Q5P InteractionNo. Cases27495121227589903465Person-Years39208472475722734953587643981545853554013473356521Age-Adjusted RR1.0 (ref)1.43 (0.89, 2.29)1.22 (0.76, 1.96)0.8 (0.45, 1.42)0.5 (0.28, 0.88)1.0 (ref)0.97 (0.72, 1.33)0.79 (0.58, 1.07)0.47 (0.31, 0.70)0.54 (0.39, 0.76)0.73MV-Adjusted* RR1.0 (ref)1.56 (0.97, 2.51)1.32 (0.82, 2.12)0.89 (0.50, 1.59)0.61 (0.34, 1.09)1.0 (ref)1.0 (0.73, 1.37)0.85 (0.63, 1.17)0.51 (0.33, 0.76)0.68 (0.49, 0.96)0.69WesternBelow MeanAbove MeanQ1Q2Q3Q4Q5Q1Q2Q3Q4Q5P InteractionNo. Cases21362839465270567699Person-Years47397493484783747589452834552947913473574644785Age-Adjusted RR1.0 (ref)1.49 (0.86, 2.56)1.26 (0.71, 2.23)1.71 (1.00, 2.93)2.22 (1.31, 3.74)1.0 (ref)1.21 (0.85, 1.74)0.98 (0.67, 1.43)1.35 (0.94, 1.93)1.88 (1.34, 2.65)0.72MV-Adjusted* RR1.0 (ref)1.34 (0.78, 2.32)1.07 (0.60, 1.90)1.33 (0.76, 2.34)1.63 (0.91, 2.93)1.0 (ref)1.17 (0.81, 1.68)0.93 (0.63, 1.38)1.27 (0.87, 1.84)1.77 (1.19, 2.61)0.64

*Adjusted for age (continuous), menopause, use of hormone therapy (never, past or current), history of hypertension, systolic and diastolic blood pressure (continuous), alcohol (continuous), total energy intake (continuous), and intake of meat, seafood, and dairy foods (continuous).

Conclusion:

In this prospective female cohort that ascertained gout with standardized criteria over 32 years, regardless of genetic predisposition, DASH diet was similarly associated with lower risk of incident gout while Western diet was associated with a higher risk. The anticipated absolute impact of diet among genetically predisposed females was larger with greater absolute risk difference. These data agree with the recent GBD Study’s recommendation for intensive dietary and anti-obesity measures for gout prevention, especially in females.1

References:

[1]Xia et al., PMID 31624843

[2]Keller et al., PMID: 28487277

[3]Tin et al., PMID 31578528

[4]Wallace et al., PMID: 856219

Acknowledgements:

The authors thank the participants of the NHS.

CY is supported by the Rheumatology Research Foundation Scientist Development Award and NIH T32 AR007258. HC is supported by NIH P50AR060772 and R01AR065944.

Disclosure of Interests:

None declared

Development and validation of stability-indicating RP-HPLC method for estimation of dalfampridine in bulk drug and tablet dosage form

Background

In the current study, a simple, improved, precise, rapid, and accurate reverse phase liquid chromatographic method was produced for the estimation of dalfampridine in bulk and tablet dosage form which is a potassium channel blocker used for the treatment of multiple sclerosis (MS). The separation of dalfampridine was achieved isocratically on a C18 column (250 × 4.6 mm, 5 μm) using (0.1% v/v) buffer pH 3.0 ± 0.05 adjusted with diluted orthophosphoric acid (OPA) and acetonitrile (ACN) in the ratio of 60:40% (v/v) as a mobile phase, at a flow rate of 0.5 mL/min, and column temperature of 40 °C. HPLC grade methanol as diluents was used. Five microliters of the standard solution of the drug was injected, and the eluted analytes were detected at 262 nm.

Results

Dalfampridine was eluted at 4.5 min with a run time of 10 min. Linearity in the method was measured in the concentration range of 25–75 ppm with a correlation coefficient of 0.999. Limit of detection and limit of quantitation were found to be 0.711 μg/mL and 2.154 μg/mL, respectively. Dalfampridine was subjected for forced degradation stability study in conditions of thermal, acid, alkali, and oxidation and photo-degradation condition. The degradants were well resolved from the dalfampridine main peak. Validation of the developed method is carried as per USFDA and ICH guidelines.

Conclusion

The results of the analysis prove that the method is simple, improved, precise, accurate, and rapid for estimating the content of dalfampridine in bulk drug and tablet dosage form and can be applied for routine analysis.