SARS-CoV-2 evolved during advanced HIV disease immunosuppression has Beta-like escape of vaccine and Delta infection elicited immunity

Characterizing SARS-CoV-2 evolution in specific geographies may help predict the properties of variants coming from these regions. We mapped neutralization of a SARS-CoV-2 strain that evolved over 6 months from the ancestral virus in a person with advanced HIV disease. Infection was before the emergence of the Beta variant first identified in South Africa, and the Delta variant. We compared early and late evolved virus to the ancestral, Beta, Alpha, and Delta viruses and tested against convalescent plasma from ancestral, Beta, and Delta infections. Early virus was similar to ancestral, whereas late virus was similar to Beta, exhibiting vaccine escape and, despite pre-dating Delta, strong escape of Delta-elicited neutralization. This example is consistent with the notion that variants arising in immune-compromised hosts, including those with advanced HIV disease, may evolve immune escape of vaccines and enhanced escape of Delta immunity, with implications for vaccine breakthrough and reinfections.

HIGHLIGHTS

A prolonged ancestral SARS-CoV-2 infection pre-dating the emergence of Beta and Delta resulted in evolution of a Beta-like serological phenotypeSerological phenotype includes strong escape from Delta infection elicited immunity, intermediate escape from ancestral virus immunity, and weak escape from Beta immunityEvolved virus showed substantial but incomplete escape from antibodies elicited by BNT162b2 vaccination.

GRAPHICAL ABSTRACT

What data is currently collected on social prescribing outcomes?Case studies of two sites in England

Whilst a considerable amount of social prescribing activity is taking place across the North West of England, little is known about how different models are being implemented, how data is being collected to support evidence of impact and outcomes, and how these models could be positively or negatively influencing health inequalities. Our study aims to investigate the reach and impact of two social prescribing services by using a mixed-methods approach which will include analysing secondary data from social prescribing management databases held by participating organisations, workshops, focus groups and interviews. Participants will include professionals involved in commissioning, delivery and monitoring and evaluation roles related to social prescribing link workers and members of the public who have accessed social prescribing services. Observational data will also be collected during meetings and informal conversations with those involved in the project. The findings will be reviewed with participants to support the development of a larger research project to explore the effects of social prescribing on health inequalities in ways that are meaningful to stakeholders. In this presentation the findings will be presented and discussed loosely around the following questions: 1. What routinely collected outcome data is currently available to social prescribing researchers (locally, nationally and internationally)?; 2.What is missing from that data regarding meaningful outcomes in relation to health inequalities?; 3. How might social prescribing reduce or exacerbate health inequalities?

A SARS-CoV-2 variant elicits an antibody response with a shifted immunodominance hierarchy

Many SARS-CoV-2 variants have mutations at key sites targeted by antibodies. However, it is unknown if antibodies elicited by infection with these variants target the same or different regions of the viral spike as antibodies elicited by earlier viral isolates. Here we compare the specificities of polyclonal antibodies produced by humans infected with early 2020 isolates versus the B.1.351 variant of concern (also known as Beta or 20H/501Y.V2), which contains mutations in multiple key spike epitopes. The serum neutralizing activity of antibodies elicited by infection with both early 2020 viruses and B.1.351 is heavily focused on the spike receptor-binding domain (RBD). However, within the RBD, B.1.351-elicited antibodies are more focused on the "class 3" epitope spanning sites 443 to 452, and neutralization by these antibodies is notably less affected by mutations at residue 484. Our results show that SARS-CoV-2 variants can elicit polyclonal antibodies with different immunodominance hierarchies.

Statin induced myalgia on high intensity statin in patients with Acute Coronary Syndrome

Background

High intensity statins are recommended in patients with acute coronary syndrome. Statins inhibit atherosclerotic plaque formation in the coronary arteries and reducing the burden of ischemic heart disease, therefore decreasing the morbidity and mortality. Muscle symptoms are most common adverse effect of statins. Hence, the aim of this study is to determine the statin induced myalgia by the statin myalgia clinical score.

Purpose

To monitor the Statin induced myalgia on high intensity statin in patients with Acute Coronary Syndrome

Methods

This was an prospective observational study comprised of 418 patients with acute coronary syndrome who were commenced on high intensity statins (Rosuvastatin 20–40mg & Atorvastatin 40–80). These patients were followed at 4 weeks, 8 weeks and 12 weeks subsequently and the clinical myalgia score (SAMS-CI) was calculated at each visit to determine the statin induced myalgia. SAMS-CI was categorized as unlikely (2–6), possible (7–8) and probable (9–11)

Results

From 418 patients, 327 were males and 91 were females. Mean age was 55.6±11.14. Only 19 (7.63±1.8) patients developed muscle symptoms on high intensity statins (Rosuvastatin 20 mg and Atorvastatin 40 mg) on SAMS-CI Score. 5 patients were unlikely to develop myalgia on SAMS-CI and continued with the same dosage without any new symptoms. 6 patients were possible on SAMS-CI, therefore the dosage of these patients were decreased to moderate intensity statin (Rosuvastatin 10mg, Atorvastatin 20 mg), their symptoms were resolved and continued with the moderate intensity statins. Furthermore, Statin was hold in 8 patients in the probable category for 4 weeks until the resolution of symptoms followed by moderate intensity statins.

Conclusion

Statin induced myalgia is more reported in old aged and female patients. Most of the patients can better tolerate the lower range of high intensity statins with the similar benefits and should be prescribed in every patient

Funding Acknowledgement

Type of funding sources: None.

An evaluation of patient outcomes following transcatheter pulmonary valve implantation: a meta-analysis

Background

Transcatheter pulmonary valve implantation has emerged as an effective alternative to surgery in patients with congenital Right Ventricular Outflow Tract Dysfunction (RVOT). There is demonstrable evidence that Percutaneous Pulmonary Valve Implantation (PPVI) effectively restores conduit graft viability with a consequent improvement in right ventricular pressures.

Aim

The objective of this study was to perform a meta-analysis of all previously published studies examining the outcome of PPVI and the associated early and late peri-procedural factors in patients with RVOT dysfunction. Data from procedures performed within our own centre have also been included.

Methodology

We performed a meta-analysis of all observational studies investigating early and late outcomes following PPVI. Risk ratios and risk differences were pooled in a random-effects model. The I2 statistic was used to quantify heterogeneity between studies. We searched EMBASE, MEDLINE, CINAHL, PsychInfo and Cochrane databases from their inception until 2021. Studies were included if they reported any comparative data regarding study endpoints. Primary endpoint was mean RVOT gradient. Secondary end points include pulmonary regurgitation fraction, left and right ventricular end-diastolic and systolic volume indexes, and left ventricular ejection fraction. Complication rates were considered a safety endpoint.

Results

A total of 23 studies with 1501 participants enrolled were included in the final meta-analysis. The RVOT gradient decreased significantly [weighted mean difference (WMD) = −20.32 mmHg; 95% confidence interval (CI): −22.15, −19.11; p<0.001]. Mean right ventricular (RV) systolic pressures fell significantly [(WMD)= −18.4 mmHg; 95% CI: −16.4, −20.2; p<0.001) and RV diastolic pressures decreased significantly [(WMD) = −6.3 mmHg, 95% CI: −4.3, −8.9; p<0.001). Pulmonary regurgitation fraction (PRF) also decreased notably (WMD = −24.38%, 95% CI: −28.27, −17.32; p<0.001).The incidence of infective endocarditis was 1.8% (95% CI: 0.7–3.8).

Conclusion

PPVI is an effective and safe strategy in relieving right ventricular remodelling and improving haemodynamic and clinical outcomes in patients with RVOT dysfunction. Multi-centre collaborations are essential to further determine the long-term effects of PPVI on cardiac function, exercise tolerance and quality of life in RVOT dysfunction.

Funding Acknowledgement

Type of funding sources: None.

1133 Long Term Survival After Standard EVAR: Have We Started to Treat The EVAR-2 Patient?

Aim

Abdominal aortic aneurysm repair was traditionally preformed with open surgical repair (OSR). Recently endovascular aneurysm repair (EVAR) has increased in popularity due to its less invasive nature particularly in those deemed unfit for OSR. The EVAR-2 trial found no significant difference between BMT and EVAR in the 30 days all-cause mortality. This questioned whether EVAR was the best option in those medically unfit for OSR.

Method

Elective EVAR procedures from the 1st April 2012 to 1st September 2017 were analysed with Kaplan-Meier graphs. The patient data was stratified by year, age group and EVAR risk scoring.

Results

The all-cause mortality at 30 days was 1.8%, at 6 months it was 7%, and at 4 years it was 19.8%. There was no significant difference with log rank analysis of the year of EVAR operation and consultant (P > 0.05). The log rank analysis found a significant difference between the stratified age groups (P < 0.001) and the EVAR scoring (P = 0.032). At all time-points the RLUH EVAR patients had a lower all-cause mortality compared to the EVAR-2. At the 4-year time point, the RLUH EVAR group had lower all- cause mortality than both EVAR-1 and EVAR-2 trials.

Conclusions

The retrospective audit data from 2012-2017, suggest the RLUH EVAR treatment practice is not falling into the EVAR-2 trial findings. At all time-points the RLUH EVAR patients had a lower all-cause mortality compared to the EVAR-2. Therefore, it can be concluded the RLUH is not treating EVAR-2 patients.

1034 A Survey to Assess the Confidence and Knowledge of Foundation Year One Doctors to Perform A Digital Rectal Examination

Aim

Digital Rectal Examination (DRE) is an essential component of comprehensive assessment of a surgical patient, both in acute and elective settings. Due to the intimate nature of the examination, this important examination is often not well taught. This study aims to assess the confidence and knowledge of the Foundation Year 1 (FY1) doctors in performing DRE.

Method

FY1 doctors were invited for online voluntary anonymous survey via Google forms. The survey consisted of 16 questions on the indications, findings, and interpretation of DRE. The purpose and aims of the study were explained in an invitation email and participants provided a declaration of consent, giving permission for their anonymous results to be used in the study.

Results

There were 24 responses, 79% had performed DRE (including on mannequins and simulations) less than 10 times. Two thirds of DRE were performed during the FY1 rotation and two thirds in the elective wards. Majority of respondents (83%) were moderately confident in performing and appreciating DRE findings. 63% respondents though that a chaperone is not mandatory if the gender of the doctor and patient was same. 58% respondents thought that hematuria is not an indication to preform DRE. Interpretation of DRE findings - approximately 80% respondents correctly interpreted the findings, however only 45% could formulate the correct initial management plan.

Conclusions

This study illustrates that FY1 doctors receive inadequate exposure to performing and interpreting DRE. Their teaching should be enhanced by providing them with more opportunities through simulation and dedicated teaching sessions.

964 Stage Migration in Newly Diagnosed Oesophago-Gastric Cancer During the First Wave Of COVID-19 Pandemic

Aim

Covid-19 has significantly disrupted elective and emergency health care provision including cancer care within the UK. The aim of the study was to investigate the impact of the pandemic on the staging of oesophago-gastric cancers at presentation, determine the time delay in performing gastroscopy and the multidisciplinary team (MDT) treatment outcomes.

Method

A retrospective cohort study of all newly diagnosed oesophago-gastric cancers (adenocarcinoma and squamous cell carcinoma) in a single regional MDT was performed between 1st October 2019 and 30th September 2020. Electronic records were interrogated and patients dichotomised into two groups with those presenting before the introduction of the UK national lockdown of 23rd March 2020 compared to those presenting post-lockdown.

Results

349 new oesophago-gastric cancer patients were discussed in the MDT (192 pre-lockdown versus 157 post-lockdown). Demographics were evenly matched between the two groups. More patients presented as an emergency admission post-lockdown (28.0% vs 12.5%, p < 0.001). Median waiting time for gastroscopy was longer post-lockdown (23 vs 14 days, p = 0.035). Metastatic disease at presentation was more frequent post-lockdown (47.8% vs 33.3%, p = 0.008). Overall, more patients had a palliative rather than curative treatment intent post-lockdown (71.3% vs 57.8%, p = 0.005).

Conclusions

The Covid-19 pandemic has had a significant negative effect on the stage of oesophago-gastric cancers at presentation. This has translated into more patients receiving palliative treatment and ultimately having a poorer prognosis. This study highlights the importance of maintaining cancer services during Covid-19 pandemic.

1120 Clinical Applications of Local Field Potentials in Deep Brain Stimulation

Aim

Local field potentials (LFP) are gathered when deep brain stimulation (DBS) electrodes are inserted into subcortical structures; however, the clinical application of these findings are unclear.

Method

A literature search was conducted using PRISMA guidelines, 231 papers were analysed for the literature review.

Results

The lack of dopamine in Parkinson’s disease (PD), is thought to increase the sensitivity of the basal ganglia-thalamo-cortical network to rhythmic oscillatory inputs causing pathological oscillations. Beta band frequency oscillations have been strongly linked to bradykinesia and rigidity in Parkinson’s disease patients. Whereas gamma oscillations were found to be prokinetic and possibly related to normal physiology. There has been varying views on LFP findings and tremor pathology, recent research has suggested a link between the ratio of slow and fast oscillations increasing resulting in a tremor. Studies found contradicting results with pathological oscillations, reasons for the variation include the time of the LFP recordings and the placement of the electrodes. The use of LFP presents a promising new technology namely adaptive deep brain stimulation (aDBS). aDBS has not been tested long-term in human patients, the safety and effectiveness long-term is unknown.

Conclusions

aDBS provide an exciting new technology however, the current evidence base provides a proof-of- principle, there are still many issues which need to be addressed before this can become an established treatment. With technological advances aDBS could revolutionise PD treatment and if perfected could potentially abolish patient’s symptoms completely.

973 Why Are Curative Treatment Rates So Low for Stage I/II Oesophago-Gastric Cancer in The West of Scotland?

Aim

Over the last decade, quality performance indicators (QPIs) have been used to drive improvements in cancer care in Scotland. QPI-11 targets curative treatment rates for oesophago-gastric (OG) cancer and this target has been consistently missed. This study aimed to investigate why patients with potentially curable Stage I and II OG cancer did not receive curative treatment in the West of Scotland.

Method

The West of Scotland MCN database was interrogated for patients with newly diagnosed stage I and II OG cancer between January 2018 and December 2019 to identify those patients who did not have curative treatment. Electronic records were then analysed.

Results

81 patients (mean age of 79.3 ± 8.9 years; 41 (50.6%) female) were identified. Median Scottish Index of Multiple Deprivation was 3 (IQR 1-7). There were 46 (56.8%) oesophageal cancers, 49 (60.5%) adenocarcinomas and 63 (77.8%) were Stage II cancers. Formal CPEX fitness was assessed in only 6 patients (7.4%). Reasons for curative treatment not being received were as follows: not clinically fit (n = 69 (85.2%)); patient declined curative treatment (n = 7 (8.6%)); disease progression (n = 3 (3.7%)) and identification of synchronous cancers (n = 2 (2.5%)). 61 patients (75.3%) are deceased at the time of analysis, with a median time from MDT discussion to death of 6 (IQR 2-11.5) months.

Conclusions

Lack of fitness for radical treatment is the predominant reason for Stage I and II OG cancer patients in the West of Scotland not being treated with curative intent. This may be related to the previously described “West of Scotland” effect on health comorbidities.

377 Expanding the Use of Wide-Awake Local Anaesthesia Non-Tourniquet (WALANT) Technique in The Management of Hand Trauma Patients During the COVID 19 Pandemic

Aim

COVID19 produced a unique challenge to the management of hand trauma. There was reduced theatre capacity and inpatient beds as staff and resources were lost to make way for the critically unwell¹, however the burden of patients (albeit reduced) requiring emergency procedures remained². During 1^stUK peak we adopted a one-stop hand trauma clinic where patients were assessed by senior surgeons and immediately operated on under local anaesthesia with Adrenalin, a model mirrored by other units across the UK during this time^3,4. Subsequent to surgery they were either seen on the same day for advice with a hand therapist or booked for immediate hand therapy follow up.

Method

A retrospective review of 158 cases operated on over a 4-month COVID19 period compared to the same 4-month period 1 year previously. Indications for surgery and type of anaesthesia were recorded. Follow up and complication rates were reviewed for the COVID19 patients.

Results

There were similarities in the demographic of patients across both cohorts and in mechanism of injury, with trauma the highest indication for surgery. The comparable data sets showed only 21% of patients treated used WALANT pre-COVID19 versus 100% of patient during COVID19.

Conclusions

WALANT is a viable model by which to perform emergency hand trauma surgery in a low cost and low resource setting. Previously this model was not utilised to full effect in our hospital. The results demonstrate the adaptability of WALANT in an adverse and dynamic situation, such as COVID19, thus highlighting benefits to patient care and service provision.

1385 “Pre-Op Fasting Times Audit in Colorectal Surgery at A University Teaching Hospital”

Aim

Hull University teaching hospitals NHS trust has guidelines for patient fasting times prior to major elective surgery. We aimed to assess the compliance of pre-op fasting times for patients undergoing elective colorectal surgery.

Method

An initial and later re-audit was undertaken, prospectively, of 20 consecutive patients admitted for elective colorectal surgery at Castle Hill Hospital. Data was collected on a structured proforma and was completed following patient’s interview, ORMIS (operation room system) and Lorenzo (hospital intranet).

Results

Initial audit demonstrated 10% (2 out of 20) and 5% (1 out of 20) compliance with liquid and solid fasting times, respectively. Following implementation of changes, re-audit demonstrated 60% (12 out of 20) and 0% (0 out of 20) compliance with liquid and solid fasting times respectively

Conclusions

We concluded that liquid fasting times can be improved further by communication between theatre staff and ward. Whilst solid fasting times can be improved but at an expense of losing a theatre space. A further re-audit [planned in a month period.

1282 Evaluation of the Basket in Catheter Technique for Transcystic Bile Duct Exploration and Suspected Ductal Stones

Aim

The ‘Basket-in-catheter’ (BIC) technique facilitates laparoscopic transcystic ductal exploration (LTCE) and increases its success rate, being easier and safer than inserting the basket alone. This study evaluates the benefits in confirmed and suspected ductal stones.

Method

Prospective preoperative, operative and postoperative data on consecutive single session ductal explorations was collected over 28 years and analysed. BIC became our default technique for the transcystic approach to confirmed or suspected bile duct stones.

Results

741 of 1225 (60.5%) attempted LTCE were performed using retrieval baskets without dilating the cystic duct (CD). BIC was used in 646 (87.2%). Of 386 (52.1%) patients undergoing successful stone retrieval 62.7% had clinical and radiological risk factors for ductal stones and 92.0% had positive intraoperative cholangiography. 355 (47.9%) patients had preoperative or operative risk factors for CBD stones and equivocal cholangiography in 25%. Basket trawling was negative and repeat cholangiography confirmed resolution of abnormalities. Choledochoscopy was utilised in 484/1225 (39.5%), either primarily or when blind trawling failed to extract stones. Retained stones occurred in 7 patients, six requiring ERCP. Bile leakage occurred in 6 patients. There were two open conversions, no biliary injuries and no mortality. Post-operative pancreatitis occurred in 7 and recurrent stones in 8 patients.

Conclusions

The BIC technique achieves successful LTCE without CD dilatation in 40%, reducing the need for choledochoscopy and choledochotomy. It facilitates safe and speedy CBD trawling when stones are suspected due to preoperative or operative risk factors or equivocal cholangiography and helps surgeons acquire and consolidate ductal exploration skills.

982 Higher General Surgical Trainee preferences for Annual Review of Competency Progression during COVID-19 Pandemic

Aim

The COVID-19 pandemic has caused significant disruption in surgical training. We aim to explore the preferences of higher general surgical trainees for Annual Review of Competency Progression (ARCP) also compare the responses across different training grades.

Method

All higher general surgical trainee in a single deanery were invited to participate in an online voluntary anonymous survey. The respondents were divided in two groups: junior (ST3-ST5) and senior higher surgical trainees (ST6-ST8) and responses compared.

Results

Sixty-four of 88 trainees responded. Thirty-three (51.6%) were ST3–ST5, 24 (37.5%) were ST6–ST8 and 7 (10.9%) were out-of-training. More trainees in ST3–ST5 group preferred to defer the next rotation for 12 months (18.2% vs 0%, p = 0.034), repeat current sub-specialty (33.3% vs 4.2%, p = 0.009), or add 12 months to training and delay predicted CCT date by 12 months (18.2% vs 0%, p = 0.034). Most trainees in both groups preferred the option of prolonging training should be offered to all trainees with an option to decline extension if ARCP competencies met (66.7% vs 50.0%, p = 0.276).

Conclusions

The preference for ARCP and length of training was different between two training groups, hence the need of trainees should be considered by training committees when addressing the impact of COVID-19.

HIV status alters disease severity and immune cell responses in Beta variant SARS-CoV-2 infection wave

There are conflicting reports on the effects of HIV on COVID-19. Here, we analyzed disease severity and immune cell changes during and after SARS-CoV-2 infection in 236 participants from South Africa, of which 39% were people living with HIV (PLWH), during the first and second (Beta dominated) infection waves. The second wave had more PLWH requiring supplemental oxygen relative to HIV-negative participants. Higher disease severity was associated with low CD4 T cell counts and higher neutrophil to lymphocyte ratios (NLR). Yet, CD4 counts recovered and NLR stabilized after SARS-CoV-2 clearance in wave 2 infected PLWH, arguing for an interaction between SARS-CoV-2 and HIV infection leading to low CD4 and high NLR. The first infection wave, where severity in HIV negative and PLWH was similar, still showed some HIV modulation of SARS-CoV-2 immune responses. Therefore, HIV infection can synergize with the SARS-CoV-2 variant to change COVID-19 outcomes.

T cell derived HIV-1 is present in the CSF in the face of suppressive antiretroviral therapy

HIV cerebrospinal fluid (CSF) escape, where HIV is suppressed in blood but detectable in CSF, occurs when HIV persists in the CNS despite antiretroviral therapy (ART). To determine the virus producing cell type and whether lowered CSF ART levels are responsible for CSF escape, we collected blood and CSF from 156 neurosymptomatic participants from Durban, South Africa. We observed that 28% of participants with an undetectable HIV blood viral load showed CSF escape. We detected host cell surface markers on the HIV envelope to determine the cellular source of HIV in participants on the first line regimen of efavirenz, emtricitabine, and tenofovir. We confirmed CD26 as a marker which could differentiate between T cells and macrophages and microglia, and quantified CD26 levels on the virion surface, comparing the result to virus from in vitro infected T cells or macrophages. The measured CD26 level was consistent with the presence of T cell produced virus. We found no significant differences in ART concentrations between CSF escape and fully suppressed individuals in CSF or blood, and did not observe a clear association with drug resistance mutations in CSF virus which would allow HIV to replicate. Hence, CSF HIV in the face of ART may at least partly originate in CD4+ T cell populations.

Sero-epidemiology and risk factor analysis of human brucellosis in Punjab, Pakistan: a cross sectional study

Human brucellosis is a neglected zoonotic problem worldwide with a high degree of morbidity in humans and is mostly overlooked due to other febrile conditions. The aim of this study was to evaluate the sero-prevalence and risk factors of human brucellosis among subjects living in Punjab, Pakistan. In this cross-sectional study, human blood samples were collected from seven districts of Punjab, Pakistan. Information regarding personal data, demographic data and potential risk factors was collected through a structured questionnaire. Detection of anti-Brucella antibodies was done through Rose Bengal Plate Test (RBPT) and Enzyme Linked Immunosorbent Assay (ELISA). Descriptive analysis, Chi square test and Odds ratio was applied using STATA software version 12. The sero-prevalence of human brucellosis was 13.13% with significantly higher percentage in males 17.23% and age group 25-40 years 16.50% (P=< 0.001). The demographic factors positively associated with human brucellosis were lack of education (P = 0.003; OR = 1.85) and farming as an occupation (P =<0.001; OR = 2.50) Similarly, among the risk factors studied, keeping animals at home (P =<0.001; OR = 2.03), slaughtering of animals (P =<0.001; OR = 15.87) and consuming raw milk (P =<0.001; OR = 5.42) were the factors strongly connected with human brucellosis. A massive awareness should be given to livestock farmers and individuals directly linked to animals regarding risk factors and transmission of brucellosis. Consumption of unpasteurized milk and its products should be condemned to curtail this neglected disease.

P–625 Does endogenous progesterone play a role in unexplained infertility? A systematic review

Study question

Does endogenous progesterone play a role in unexplained infertility? A systematic review investigating the possibility of altered progesterone-mediated change leading to reduced endometrial receptivity in women with unexplained infertility.

Summary answer

The evidence suggests that many of the measurable actions of endogenous progesterone are reduced in women with unexplained infertility when compared with controls.

What is known already

Unexplained infertility is the diagnosis given to heterosexual couples who fail to conceive despite normal semen analysis, regular ovulation and patent tubes. The underlying pathology is likely to relate to embryonic failure to implant. Endometrial receptivity is largely mediated by luteal phase progesterone which controls many different molecular pathways involved in secretory transformation. It is possible that defective actions of progesterone could contribute to this condition. To date however, there is minimal published literature on the role of progesterone in unexplained infertility. We therefore felt it important to combine the results of all trials measuring progesterone-related outcomes in unexplained infertility.

Study design, size, duration

A systematic review was performed using standard Cochrane methodology. We searched Medline, Embase and CINAHL databases from inception to December 2020 and additionally hand-searched. The study was prospectively registered on Prospero (CRD42020141041). The search strategy was designed to identify all types of primary research published in English that investigated women with unexplained infertility and reported outcomes that relate to progesterone. Newcastle Ottawa Scoring and NHLBI assessment of bias scoring was performed.

Participants/materials, setting, methods

The study population was women with unexplained infertility. Included studies had no controls, fertile controls or controls with other diagnoses associated with subfertility. Outcomes were either upstream affecting progesterone production/release or receptor expression or downstream measuring results of progesterone-mediated processes. The results were summarised in a narrative review. Meta-analysis was not possible due to varying methodological heterogeneity.

Main results and the role of chance

36 studies were included. No difference was found in 18 studies in progesterone levels (serum, peritoneal and salivary) between women with unexplained infertility and control groups. Despite this, 32 of the 36 included studies demonstrated a significant difference between progesterone-mediated outcomes in the unexplained infertile and control groups.

5 ultrasound studies all reported increased resistance and decreased flow on doppler studies of uterine, ovarian and spiral arteries and reduced endometrial and sub-endometrial perfusion. No significant difference was found in luteal phase endometrial thickness in 2 studies.

Endometrial dating was reported by 11 studies. 8/11 studies reported significantly higher numbers (20–38%) of ‘out-of-phase’ endometrium in women with unexplained infertility compared with controls.

Endometrial biopsy results measuring different cell adhesion molecules, monoclonal antibodies and other molecules involved in endometrial transformation as well as expression of responsible genes and steroid hormone receptors were included. All the progesterone-mediated outcome measures listed above were reduced in unexplained infertile women except β3 integrin which reported contradictory results and SGK1 expression which was reported in 1 study. This trend towards support for the hypothesis may be more important than any individual finding. The quality of the included studies was variable and hence the strength of the recommendations moderate.

Limitations, reasons for caution

The number of studies measuring each outcome was limited. The study quality varied from good to poor. Methodological heterogeneity between studies prevented meta-analysis. The strength of the study however comes from the originality of the research, the variety of included outcomes and that 32/36 papers reported results supporting the hypothesis.

Wider implications of the findings: The findings of this systematic review support the need for larger, well designed research on this topic. If altered progesterone-mediated receptivity is implicated in unexplained infertility, it may be possible to offer other therapeutic interventions to improve outcomes as an alternative or adjunct to standard fertility treatment.

Trial registration number

NA