Prescribed Drugs and the Microbiome

Antibiotic or gastric acid inhibitor use during pregnancy and postpartum depression: Population-based cohort study

INTRODUCTION

Postpartum depression is one of the most common non-obstetric postnatal complications. As the microbiome (and gut-brain axis) as well as inflammation may be involved in the mechanism, we aimed to assess if antibiotic or gastric acid inhibition use during pregnancy affects the risk of postpartum depression (clinical diagnosis and/or antidepressant use up to 1 year after childbirth).

MATERIAL AND METHODS

This population-based cohort study used first singleton pregnancy resulting in a live birth in Sweden from 2006 to 2016. Women with history of depression were excluded. Multivariable logistic regression models were used to assess the impact of antibiotics and gastric acid inhibitors and other risk factors, presented as odds ratios (ORs) with 95% confidence intervals (CI).

RESULTS

Overall, 29% of all 10 666 women with postpartum depression were exposed to antibiotics and 6.2% to gastric acid inhibitors, compared to, respectively, 21% and 3.2% of 613 205 women without postpartum depression. Antibiotic use during pregnancy was associated with postpartum depression (OR 1.43, 95% CI 1.37-1.49), particularly for quinolones and other antibacterials (including nitroimidazole derivatives). Gastric acid inhibition was associated with an even higher risk than antibiotics (OR 2.04, 95% CI 1.88-2.21). Both antibiotics and gastric acid inhibitors suggested higher risk with increased dose in a dose-response analysis.

CONCLUSIONS

The use of antibiotics and gastric acid inhibition drugs during pregnancy appeared to be associated with a higher risk of postpartum depression. However, it is important to consider that other predisposing factors could contribute to this increased risk, even after excluding individuals with a history of depression.

Clostridioides difficile recurrence in individuals with and without cancer: a Swedish population-based cohort study

PURPOSE

Patients with cancer are vulnerable to Clostridioides difficile infection (CDI) due to their disease, treatment and regular hospital contact, yet if CDI-recurrence is more common remains unclear, and differences among cancer types remain unexplored.

METHODS

This Swedish nationwide population-based cohort included all 43,150 individuals with recorded CDI (2006-2019) to assess CDI-recurrence in individuals with and without cancer, with binary multivariable logistic regression, stratified by anatomical location, and survival status.

RESULTS

Compared to those without cancer (N = 29,543), ongoing cancer (diagnosis < 12 months; N = 3,882) was associated with reduced recurrence (OR = 0.81, 95% CI 0.73-0.89), while there was no association with cancer history (diagnosis ≥ 12 months; N = 9,725). There was an increased 8-week all-cause mortality (Ongoing cancer: OR = 1.58, 95% CI 1.43-1.74; Cancer history: OR = 1.45, 95% CI 1.36-1.55) compared to those without cancer. Among CDI-survivors, those with ongoing cancer presented with a decreased odds of recurrence (OR = 0.84, 95% CI 0.76-0.94), compared to those without cancer history, with no association for those with cancer history (OR = 1.04, 95% CI 0.97-1.1). Large variations were seen across cancer types, with the highest observed proportion of recurrence in oral and mesothelial cancer, and the lowest for esophageal cancer, although no statistically significant OR were found.

CONCLUSION

The population-based study indicates that individuals with cancer may have fewerrecurrences than expected, yet variations by cancer type were large, and mortality was high.

The combined effect of systemic antibiotics and proton pump inhibitors on Clostridioides difficile infection and recurrence

BACKGROUND

Antibiotics and proton pump inhibitors (PPI) are recognized risk factors for acquisition and recurrence of Clostridioides difficile infection (CDI), yet combined effects remain unclear.

OBJECTIVES

To assess the short- and long-term effects of antibiotics and PPIs on CDI risk and recurrence.

METHODS

Population-based study including all 43 152 patients diagnosed with CDI in Sweden (2006-2019), and 355 172 matched population controls without CDI. The impact of antibiotics and PPIs on CDI risk and recurrence was explored for recent (0-30 days) and preceding (31-180 days) use prior to their first CDI diagnosis, using multivariable conditional logistic regression presented as odds ratios (ORs) and 95% confidence interval, adjusted for demographics, comorbidities and other drugs.

RESULTS

Compared to controls, the combined effect of recent PPIs and antibiotics [ORAB+PPI = 17.51 (17.48-17.53)] on CDI risk was stronger than the individual effects [ORAB = 15.37 (14.83-15.93); ORPPI = 2.65 (2.54-2.76)]. Results were less pronounced for exposure during the preceding months. Dose-response analyses showed increasing exposure correlated with CDI risk [recent use: ORAB = 6.32 (6.15-6.49); ORPPI = 1.65 (1.62-1.68) per prescription increase].Compared to individuals without recurrence (rCDI), recent [ORAB = 1.30 (1.23-1.38)] and preceding [ORAB = 1.23 (1.16-1.31); ORPPI = 1.12 (1.03-1.21)] use also affected the risk of recurrence yet without significant interaction between both. Recent macrolides/lincosamides/streptogramins; other antibacterials including nitroimidazole derivates; non-penicillin beta lactams and quinolones showed the strongest association with CDI risk and recurrence, particularly for recent use. PPI use, both recent and preceding, further increased the CDI risk associated with almost all antibiotic classes.

CONCLUSION

Recent and less recent use of PPIs and systemic antibiotics was associated with an increased risk of CDI, particularly in combination.

Modulation of the Gut Microbiota by Nutrition and Its Relationship to Epigenetics

The intestinal microbiota is a community of microorganisms inhabiting the human intestines, potentially influencing both physiological and pathophysiological processes in the human body. Existing evidence suggests that nutrients can influence the modulation of the gut microbiota. However, there is still limited evidence regarding the effects of vitamin and mineral supplementation on the human gut microbiota through epigenetic modification. It is plausible that maintaining an adequate dietary intake of vitamin D, iron, fibre, zinc and magnesium may have a beneficial effect on alleviating inflammation in the body, reducing oxidative stress, and improving the condition of the intestinal microbiota through various epigenetic mechanisms. Moreover, epigenetics involves alterations in the phenotype of a cell without changing its fundamental DNA sequence. It appears that the modulation of the microbiota by various nutrients may lead to epigenetic regulation. The correlations between microbiota and epigenetics are potentially interdependent. Therefore, the primary objective of this review is to identify the complex relationships between diet, gut microbiota, and epigenetic regulation. These interactions could play a crucial role in systemic health.

Non-antibiotic compounds associated with humans and the environment can promote horizontal transfer of antimicrobial resistance genes

Horizontal gene transfer plays a key role in the global dissemination of antimicrobial resistance (AMR). AMR genes are often carried on self-transmissible plasmids, which are shared amongst bacteria primarily by conjugation. Antibiotic use has been a well-established driver of the emergence and spread of AMR. However, the impact of commonly used non-antibiotic compounds and environmental pollutants on AMR spread has been largely overlooked. Recent studies found common prescription and over-the-counter drugs, artificial sweeteners, food preservatives, and environmental pollutants, can increase the conjugative transfer of AMR plasmids. The potential mechanisms by which these compounds promote plasmid transmission include increased membrane permeability, upregulation of plasmid transfer genes, formation of reactive oxygen species, and SOS response gene induction. Many questions remain around the impact of most non-antibiotic compounds on AMR plasmid conjugation in clinical isolates and the long-term impact on AMR dissemination. By elucidating the role of routinely used pharmaceuticals, food additives, and pollutants in the dissemination of AMR, action can be taken to mitigate their impact by closely monitoring use and disposal. This review will discuss recent progress on understanding the influence of non-antibiotic compounds on plasmid transmission, the mechanisms by which they promote transfer, and the level of risk they pose.

Maintenance Proton Pump Inhibitor Use Associated with Increased All-Cause and Cause-Specific Mortality in Sweden

BACKGROUND

Proton pump inhibitor (PPI) use has increased over the last decades and has been associated with multiple adverse events and potentially even overall survival.

AIMS

We aimed to investigate the association between proton pump inhibitor maintenance use and all-cause and cause-specific mortality, addressing confounding by indication and duration of use.

METHODS

This Swedish population-based cohort study included all adult (N = 935,236) PPI and histamine-2 receptor antagonist maintenance users (≥ 180 days use) during 2005-2014. Standardised mortality ratios (SMRs) and 95% confidence intervals were calculated for all-cause and cause-specific mortality comparing the risk among PPI/H2RA users to that of the Swedish background population, stratified by age, sex, calendar period, indication and duration of use. Multivariable Poisson regression models were used to compare PPI use to H2RA use, expressed as incidence rate ratios and 95% confidence intervals.

RESULTS

PPI and histamine-2 receptor antagonist use were associated with an increased risk of all-cause mortality (SMR = 1.35; 1.34-1.36; SMR = 1.31; 1.27-1.36, respectively). The highest SMRs were found in the youngest age groups. In direct comparison, PPI use showed a higher mortality risk than histamine-2 receptor antagonist use (incidence rate ratios = 1.42; 1.38-1.46). PPIs were related to increased cancer (SMR = 1.21; 1.20-1.22), and cardiovascular mortality (SMR = 1.36; 1.35-1.37). Increased SMRs were observed for most indications. Longer duration of use was associated with a higher mortality among PPI users but not among histamine-2 receptor antagonist users.

CONCLUSION

Maintenance PPI use was associated with an increased risk of all-cause and cause-specific mortality, and the risk increased with prolonged duration.

Cohort profile: the Swedish Maternal Microbiome project (SweMaMi) - assessing the dynamic associations between the microbiome and maternal and neonatal adverse events

PURPOSE

The Swedish Maternal Microbiome (SweMaMi) project was initiated to better understand the dynamics of the microbiome in pregnancy, with longitudinal microbiome sampling, shotgun metagenomics, extensive questionnaires and health registry linkage.

PARTICIPANTS

Pregnant women were recruited before the 20th gestational week during 2017-2021 in Sweden. In total, 5439 pregnancies (5193 unique women) were included. For 3973 pregnancies (73%), samples were provided at baseline, and for 3141 (58%) at all three timepoints (second and third trimester and postpartum). In total, 38 591 maternal microbiome samples (vaginal, faecal and saliva) and 3109 infant faecal samples were collected. Questionnaires were used to collect information on general, reproductive and mental health, diet and lifestyle, complemented by linkage to the nationwide health registries, also used to follow up the health of the offspring (up to age 10).

FINDINGS TO DATE

The cohort is fairly representative for the total Swedish pregnant population (data from 2019), with 41% first-time mothers. Women with university level education, born in Sweden, with normal body mass index, not using tobacco-products and aged 30-34 years were slightly over-represented.

FUTURE PLANS

The sample and data collection were finalised in November 2021. The next steps are the characterisation of the microbial DNA and linkage to the health and demographic information from the questionnaires and registries. The role of the microbiome on maternal and neonatal outcomes and early-childhood diseases will be explored (including preterm birth, miscarriage) and the role and interaction of other risk factors and confounders (including endometriosis, polycystic ovarian syndrome, diet, drug use). This is currently among the largest pregnancy cohorts in the world with longitudinal design and detailed and standardised microbiome sampling enabling follow-up of both mothers and children. The findings are expected to contribute greatly to the field of reproductive health focusing on pregnancy and neonatal outcomes.

Patient-reported exposures and outcomes link the gut-brain axis and inflammatory pathways to specific symptoms of severe mental illness

We developed a "gut-brain-axis questionnaire" (GBAQ) to obtain standardized person-specific "review of systems" data for microbiome-gut-brain-axis studies. Individual items were compared to PANSS symptom measures using dimensional, transdiagnostic and traditional categorical approaches.

METHOD

Forty psychotic participants, independent of diagnoses, and 42 without psychosis (18 nonpsychotic affective disorders, 24 healthy controls) completed the GBAQ and underwent research diagnostic and symptom assessments. The PANSS scales and its dysphoric mood, autistic preoccupation and activation factors were computed.

RESULTS

Transdiagnostic analyses robustly linked psychosis severity to constipation (p<.001), and Negative (p=.045) and General Psychopathology scores (p=.016) with bowel hypomotility. Activation factor scores predicted numbers of psychiatric (p=.009) and medical conditions (p=.003), BMI (p=.003), skin (p<.001) and other conditions. Categorical analyses comparing psychotic, nonpsychotic and control groups revealed behavioral differences: cigarette smoking (p=.013), alcohol use (p=.007), diet (p's <.05), exercise (p<.001). All subjects accurately self-reported their diagnosis.

CONCLUSIONS

The GBAQ is a promising tool. Transdiagnostic analyses associated psychotic symptoms to gut hypomotility, indicative of low gut vagal tone, consistent with reduced cardiovagal activity in psychosis. Activation, similar to delirium symptoms, predicted medical comorbidity and systemic inflammatory conditions. Group level comparisons only showed behavioral differences. Underpinnings of psychiatric disorders may include reduced gut vagal function, producing psychosis, and systemic inflammation, impacting risks for psychotic and nonpsychotic conditions.

Importance of gut microbiome regulation for the prevention and recovery process after SARS-CoV-2 respiratory viral infection (Review)

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported to affect organs other than the lungs, including the liver, brain, kidneys and intestine, and gastrointestinal symptoms, such as nausea, vomiting, diarrhea and abdominal discomfort, have also been reported. Thus, SARS-CoV-2 could potentially directly or indirectly regulate the gut microbiome profile and its homeostasis. The abundance of Coprobacillus, Clostridium ramosum and Clostridium are associated with the severity of COVID-19, and Firmicutes, Bacteriodetes, Proteobacteria and Actinobacteria are also related to COVID-19 infection. The four phyla are correlated with the severity of COVID-19 infection in patients. The modulation of factors that control the physiological growth of the gut microbiome will determine the proportionate ratio of microbiome types (profile). Taken together, gut microbiome profile alterations in COVID-19 patients may have a cross effect with the modulation of cytokine levels in COVID-19 infection. With these findings, several factors that regulate gut microbiome homeostasis may support the degree of the clinical symptoms and hasten the recovery process after COVID-19 infection.

OUP accepted manuscript

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Conclusions

Influence of Acetylcholine Esterase Inhibitors and Memantine, Clinically Approved for Alzheimer's Dementia Treatment, on Intestinal Properties of the Mouse

Four drugs are currently approved for the treatment of Alzheimer’s disease (AD) by the FDA. Three of these drugs—donepezil, rivastigmine, and galantamine—belong to the class of acetylcholine esterase inhibitors. Memantine, a NMDA receptor antagonist, represents the fourth and a combination of donepezil and memantine the fifth treatment option. Recently, the gut and its habitants, its microbiome, came into focus of AD research and added another important factor to therapeutic considerations. While the first data provide evidence that AD patients might carry an altered microbiome, the influence of administered drugs on gut properties and commensals have been largely ignored so far. However, the occurrence of digestive side effects with these drugs and the knowledge that cholinergic transmission is crucial for several gut functions enforces the question if, and how, this medication influences the gastrointestinal system and its microbial stocking. Here, we investigated aspects such as microbial viability, colonic propulsion, and properties of enteric neurons, affected by assumed intestinal concentration of the four drugs using the mouse as a model organism. All ex vivo administered drugs revealed no direct effect on fecal bacteria viability and only a high dosage of memantine resulted in reduced biofilm formation of E. coli. Memantine was additionally the only compound that elevated calcium influx in enteric neurons, while all acetylcholine esterase inhibitors significantly reduced esterase activity in colonic tissue specimen and prolonged propulsion time. Both, acetylcholine esterase inhibitors and memantine, had no effect on general viability and neurite outgrowth of enteric neurons. In sum, our findings indicate that all AD symptomatic drugs have the potential to affect distinct intestinal functions and with this—directly or indirectly—microbial commensals.

Antibiotic use and risk of colorectal cancer: a systematic review and dose-response meta-analysis

BACKGROUND

It is understudied whether the posed association of oral antibiotics with colorectal cancer (CRC) varies between antibiotic spectrums, colorectal continuum, and if a non-linear dose-dependent relationship is present.

DESIGN

Three electronic databases and a trial platform were searched for all relevant studies, from inception until February 2020, without restrictions. Random-effects meta-analyses provided pooled effect-sizes (ES) with 95% confidence intervals (CI). Dose-response analyses modelling the relationship between number of days exposed to antibiotics and CRC risk were extended to non-linear multivariable random-effects models.

RESULTS

Of 6483 identified publications ten were eligible, including 4.1 million individuals and over 73,550 CRC cases. The pooled CRC risk was increased among individuals who ever-used antibiotics (ES = 1.17, 95%CI 1.05-1.30), particularly for broad-spectrum antibiotics (ES = 1.70, 95%CI 1.26-2.30), but not for narrow-spectrum antibiotic (ES = 1.11, 95% 0.93-1.32). The dose-response analysis did not provide strong evidence of any particular dose-response association, and the risk patterns were rather similar for colon and rectal cancer.

DISCUSSION

The antibiotic use associated CRC risk seemingly differs between broad- and narrow-spectrum antibiotics, and possibly within the colorectal continuum. It remains unclear whether this association is causal, requiring more mechanistic studies and further clarification of drug-microbiome interactions.

Antibiotic use and the risk of breast cancer: A systematic review and dose-response meta-analysis

OBJECTIVE

Oral antibiotics are posed as a possible risk factor for breast cancer. Evidence is insufficient to determine whether the choice of antibiotic class could effect this potential association, and non-linearity has not been studied. We aimed to fill these important knowledge gaps.

METHODS

PubMed, Web of Science, Embase and a trial registry were searched from inception until January 2020, without any restrictions. Additionally, extensive manual searches were undertaken. Random-effects meta-analyses provided pooled risk estimates with 95 % confidence intervals (CI). Dose-response analyses modeling the relationship between number of antibiotic prescriptions and breast cancer risk were extended to non-linear models. Heterogeneity, publication bias and small-study effects were assessed.

RESULTS

Of 7805 identified publications ten were eligible, including 3,719,383 individuals and 84,485 breast cancer cases. The pooled breast cancer risk was modestly increased among individuals who ever used antibiotics (relative risk RR = 1.18, 95 %CI 1.08-1.29), also after excluding the last year prior diagnosis. This excess risk was seen among penicillin (RR = 1.09, 95 %CI 1.01-1.18), tetracycline (RR = 1.13, 95 %CI 1.04-1.24) and nitrofuran users (RR = 1.26, 95 %CI 1.05-1.52), whilst nitroimidazole and metronidazole use (RR = 1.05, 95 %CI 1.00-1.11) indicated for marginal association. No apparent association was found for other antibiotics. Data suggested for a non-linear dose-dependent relationship, with a seemingly protective effect after at least 35 prescriptions. However, these findings might partly be explained by limited power of dose-response analyses.

CONCLUSIONS

The association of antibiotics with breast cancer risk appears to differ between the various antibiotic classes. Whether this association is causal remains unclear, requiring further clarification and mechanistic studies.

Live Biotherapeutic Products, A Road Map for Safety Assessment

Recent developments in the understanding of the relationship between the microbiota and its host have provided evidence regarding the therapeutic potential of selected microorganisms to prevent or treat disease. According to Directive 2001/83/EC, in the European Union (EU), any product intended to prevent or treat disease is defined as a medicinal product and requires a marketing authorization by competent authorities prior to commercialization. Even if the pharmaceutical regulatory framework is harmonized at the EU level, obtaining marketing authorisations for medicinal products remains very challenging for Live Biotherapeutic Products (LBPs). Compared to other medicinal products currently on the market, safety assessment of LBPs represents a real challenge because of their specific characteristics and mode of action. Indeed, LBPs are not intended to reach the systemic circulation targeting distant organs, tissues, or receptors, but rather exert their effect through direct interactions with the complex native microbiota and/or the modulation of complex host-microbiota relation, indirectly leading to distant biological effects within the host. Hence, developers must rely on a thorough risk analysis, and pharmaceutical guidelines for other biological products should be taken into account in order to design relevant non-clinical and clinical development programmes. Here we aim at providing a roadmap for a risk analysis that takes into account the specificities of LBPs. We describe the different risks associated with these products and their interactions with the patient. Then, from that risk assessment, we propose solutions to design non-clinical programmes and First in Human (FIH) early clinical trials appropriate to assess LBP safety.

Proprietary non-animal stabilized hyaluronic acid/dextranomer gel (NASHA/Dx) for endoscopic treatment of grade IV vesicoureteral reflux: Long-term observational study

BACKGROUND

Since 1993, children aged >1 year with persistent grade III-V vesicoureteral reflux (VUR) and febrile urinary tract infections (UTIs) attending Uppsala University Hospital have undergone endoscopic injection with proprietary non-animal stabilized hyaluronic acid/dextranomer gel (NASHA/Dx; Deflux®).

OBJECTIVE

Investigate long-term incidence of UTI, bladder dysfunction, ureteral reimplantation and overall clinical findings following endoscopic injection of NASHA/Dx.

STUDY DESIGN

Children with grade IV VUR diagnosed by voiding cystourethrogram (VCUG) and dilating VUR persisting for >1 year were included in this study. 15-25 years after endoscopic treatment, patients' hospital charts were studied. Information on bladder function and UTIs was obtained via questionnaire, 8-18 years after endoscopic treatment.

RESULTS

185 patients (69 boys, 116 girls) were included in the study; 237 grade IV VUR ureters were treated. All study patients were diagnosed with VUR after a febrile UTI (i.e. pyelonephritis). According to the last voiding cystourethrogram, 69% of ureters showed a positive response (VUR grade 0-I), 7% had VUR grade II and 23% had VUR grade ≥ III. 46 patients (25%) required ureteral reimplantation during follow-up. Among patients treated during the second 5-year period compared with the first (1998-2003 versus 1993-1998), there was a significant decrease in the rate of ureteral reimplantation (31% vs 16%; p = 0.0365). This difference may be attributable to developments over time in the injection technique. UTIs occurred in 30 patients (21% of the evaluable population): 28 females and 2 males. Febrile UTIs were reported in 14 patients (10%), all females. Forty-nine patients (34%) had bladder problems (e.g. underactivity, overactivity, incontinence). Five patients underwent ureteral reimplantation 'late', 6-10 years after the last endoscopic injection. In one male patient, calcification around the NASHA/Dx implantation site was observed during routine examination 2 years after endoscopic treatment; no intervention was required. No safety issues were observed in the remaining 97% of the study population.

CONCLUSIONS

This study represents the longest published follow-up of Grade IV VUR patients undergoing endoscopic treatment. Three-quarters of patients did not need ureteral reimplantation. Optimal injection technique and higher injection volume were associated with a reduced ureteral reimplantation rate. Treatment with NASHA/Dx was durable and well tolerated: long-term risks of UTI, bladder dysfunction and recurrent VUR were low.

Gut microbiota in surgical and critically ill patients

Microbiota-defined as a collection of microbial organisms colonising different parts of the human body-is now recognised as a pivotal element of human health, and explains a large part of the variance in the phenotypic expression of many diseases. A reduction in microbiota diversity, and replacement of normal microbes with non-commensal, pathogenic or more virulent microbes in the gastrointestinal tract-also known as gut dysbiosis-is now considered to play a causal role in the pathogenesis of many acute and chronic diseases. Results from animal and human studies suggest that dysbiosis is linked to cardiovascular and metabolic disease through changes to microbiota-derived metabolites, including trimethylamine-N-oxide and short-chain fatty acids. Dysbiosis can occur within hours of surgery or the onset of critical illness, even without the administration of antibiotics. These pathological changes in microbiota may contribute to important clinical outcomes, including surgical infection, bowel anastomotic leaks, acute kidney injury, respiratory failure and brain injury. As a strategy to reduce dysbiosis, the use of probiotics (live bacterial cultures that confer health benefits) or synbiotics (probiotic in combination with food that encourages the growth of gut commensal bacteria) in surgical and critically ill patients has been increasingly reported to confer important clinical benefits, including a reduction in ventilator-associated pneumonia, bacteraemia and length of hospital stay, in small randomised controlled trials. However, the best strategy to modulate dysbiosis or counteract its potential harms remains uncertain and requires investigation by a well-designed, adequately powered, randomised controlled trial.

Systematic review with meta-analysis: the risks of proton pump inhibitors during pregnancy

BACKGROUND

There have been safety concerns considering long-term proton pump inhibitor (PPI) use, also during pregnancy.

AIMS

To assess the risk of adverse neonatal outcomes associated with maternal intake of PPIs by means of systematic review and meta-analysis.

METHODS

The systematic search included PubMed, Web of Science, Cochrane Database and Embase (inception until June 2019). All studies reporting ≥1 adverse pregnancy outcome comparing PPI users to non-users. Histamine-2 receptor antagonists (H2RA) were also compared to both non-users and PPI users. Outcomes included congenital malformations, abortion, stillbirth, neonatal death, preterm birth, small for gestational age and low birth weight. Pooled odds ratios (OR) and 95% confidence intervals (CI) were obtained by random-effects modelling. PROSPERO study-protocol: CRD42018103320.

RESULTS

In total, 26 observational studies (20 cohort, 6 case-control studies) were identified, of which 19 assessed PPIs and 12 H2RA. PPI use was associated with an increased risk of congenital malformations (OR 1.28, 95% CI 1.09-1.52), especially in case-control studies (OR 2.04, 1.46-2.86). No associations were found between H2RA and congenital malformations. No significant associations were found between PPI use and abortions, stillbirth, neonatal death, preterm birth and low-birth weight, although H2RA use may be associated with an increased risk of preterm birth (OR 1.25, 95% CI 1.02-1.56). Although statistical heterogeneity and the risk of bias were overall low, clinical heterogeneity, information and selection bias may be present in the individual studies.

CONCLUSIONS

This meta-analysis suggests an association between maternal PPI use and congenital malformations in humans, yet power was insufficient to assess specific malformations and drugs.