Prescription Sequence Symmetry Analysis Research Articles

Identifying and quantifying potentially problematic prescribing cascades in clinical practice: A mixed‐methods study

AbstractBackgroundA prescribing cascade occurs when medication causes an adverse drug reaction (ADR) that leads to the prescription of additional medication. Prescribing cascades can cause excess medication burden, which is of particular concern in older adults. This study aims to identify and quantify potentially problematic prescribing cascades relevant for clinical practice.MethodsA mixed‐methods study was conducted. First, prescribing cascades were identified through literature search. An expert panel (n = 16) of pharmacists and physicians assessed whether these prescribing cascades were potentially problematic. Next, a cohort study quantified potentially problematic prescribing cascades in adults using Dutch community pharmacy data for the period 2015–2020. Additionally, the influence of multiple medications potentially causing the same ADR was evaluated. Prescription sequence symmetry analysis was used to calculate adjusted sequence ratios (aSRs), adjusting for temporal prescribing trends. An aSR >1.0 indicates the occurrence of a prescribing cascade. In a subgroup analysis, aSRs were calculated for older adults.ResultsSeventy‐six prescribing cascades were identified in literature and three were provided by experts. Of these, 66 (83.5%) were considered potentially problematic. A significant positive aSR for the medication sequence was found for 41 (62.1%) of these prescribing cascades. The highest aSR was found for amiodarone potentially causing hypothyroidism treated with thyroid hormones (4.63 [95% confidence interval 4.40–4.85]), based on 565 incident users. The biggest population (n = 34,645) was found for angiotensin converting enzyme‐inhibitors potentially causing urinary tract infections treated with antibiotics. Regarding four potential ADRs, the aSRs were higher for people using multiple medications that cause the same ADR as compared to people using only one of those medications. Among older adults the aSRs remained significant for 37 prescribing cascades.ConclusionAn overview was generated of potentially problematic prescribing cascades relevant for clinical practice. These results can support healthcare providers to intervene and reduce medication burden for older adults.

Prescribing Cascades of Loop Diuretics and Anti-vertigo Drugs Following Treatment with Gabapentinoids and Benzodiazepines: Prescription Sequence Symmetry Analysis of a Large-Scale Claims Database Including Japanese Older Adults.

Gabapentinoids (GBP) and benzodiazepines (BZ) are commonly prescribed in older adults and their package inserts list edema and vertigo as adverse drug reactions. These adverse drug reactions may be treated with symptomatic drug therapies without discontinuing the culprit drugs or decreasing their dose, thereby initiating a prescribing cascade and often resulting in polypharmacy. Whether prescribing cascades occur in the treatment of edema and dizziness among Japanese patients treated with GBP and BZ has not been investigated, including treatment with mirogabalin, a class drug of GBP marketed in Japan. We aimed to investigate prescribing cascades with GBP-induced and BZ-induced edema and dizziness treated with loop diuretics (LD) and anti-vertigo drugs (AVD), respectively, among older adults. A prescription sequence symmetry analysis design was used to detect signals of prescribing cascades associated with edema and dizziness induced by GBP and BZ (exposure drugs). Loop diuretics and AVD were the outcome drugs used to identify prescribing cascades following the initiation of exposure drugs. The study population consisted of enrollees of a large-scale health claims database provided by DeSC Healthcare, Inc., between April 2014 and March 2021. Subjects eligible for a prescription sequence symmetry analysis were patients aged ≥65 years prescribed an outcome drug within 90 days before and after exposure drug initiation. A signal of a prescribing cascade was detected if secular trend-adjusted sequence ratios were statistically significant on comparison of the frequencies of outcome drug initiation before and after exposure drug initiation. We identified 2671 patients with prescriptions of a GBP-LD combination, 4009 with a GBP-AVD combination, 8675 with a BZ-LD combination, and 9462 with a BZ-AVD combination. The adjusted sequence ratios for GBP-LD and BZ-LD cascades were significantly larger than one (adjusted sequence ratio [95% confidence interval], 1.69 [1.56-1.83]; 1.35 [1.29-1.41], respectively), indicating positive signals of prescribing cascades. No signal was detected for the GBP-AVD or BZ-AVD cascade (0.89 [0.83-0.94]; 0.90 [0.87-0.94], respectively). The adjusted sequence ratio for the mirogabalin cascade was higher than that for pregabalin (2.23 [1.84-2.71] vs 1.59 [1.46-1.73]). Our study provides good evidence that LD-prescribing cascades associated with edema would be a class effect of GBP and BZ. Edema emerging around 1 month after GBP initiation should be carefully differentiated from pathological edema, and undue LD prescription as a prescribing cascade should be avoided.

Which older adults are at highest risk of prescribing cascades? A national study of the gabapentinoid-loop diuretic cascade.

Prescribing cascades are important contributors to polypharmacy. Little is known about which older adults are at highest risk of experiencing prescribing cascades. We explored which older veterans are at highest risk of the gabapentinoid (including gabapentin and pregabalin)-loop diuretic (LD) cascade, given the dramatic increase in gabapentinoid prescribing in recent years. Using Veterans Affairs and Medicare claims data (2010-2019), we performed a prescription sequence symmetry analysis (PSSA) to assess loop diuretic initiation before and after gabapentinoid initiation among older veterans (≥66 years). To identify the cascade, we calculated the adjusted sequence ratio (aSR), which assesses the temporality of LD relative to gabapentinoid initiation. To explore high-risk groups, we used multivariable logistic regression with prescribing order modeled as a binary dependent variable. We calculated adjusted odds ratios (aORs), measuring the extent to which factors are associated with one prescribing order versus another. Of 151,442 veterans who initiated a gabapentinoid, there were 1,981 patients who initiated a LD within 6 months after initiating a gabapentinoid compared to 1,599 patients who initiated a LD within 6 months before initiating a gabapentinoid. In the gabapentinoid-LD group, the mean age was 73 years, 98% were male, 13% were Black, 5% were Hispanic, and 80% were White. Patients in each group were similar across patient and health utilization factors (standardized mean difference <0.10 for all comparisons). The aSR was 1.23 (95% CI: 1.13, 1.34), strongly suggesting the cascade's presence. People age ≥85 years were less likely to have the cascade (compared to 66-74 years; aOR 0.74, 95% CI: 0.56-0.96), and people taking ≥10 medications were more likely to have the cascade (compared to 0-4 drugs; aOR 1.39, 95% CI: 1.07-1.82). Among older adults, those who are younger and taking many medications may be at higher risk of the gabapentinoid-LD cascade, contributing to worsening polypharmacy and potential drug-related harms. We did not identify strong predictors of this cascade, suggesting that prescribing cascade prevention efforts should be widespread rather than focused on specific subgroups.

Detection of iodixanol-induced allergic reaction signals in Chinese inpatients: a multi-center retrospective database study using prescription sequence symmetry analysis.

This study aimed to explore the signal detection method for allergic reactions induced by inpatient iodixanol injection. A database of 3,719,217 hospitalized patients from 20 large Chinese general hospitals was processed and analyzed using the prescription sequence symmetry analysis (PSSA) method. 126,680 inpatients who used iodixanol and were concurrently treated with anti-allergic drugs were analyzed. In the medical records of these patients, only 32 had documented iodixanol allergies. Statistical analysis identified 22 drugs in 4 categories-calcium preparations, adrenergic/dopaminergic agents, glucocorticoids, and antihistamines-as marker drugs. With time intervals of 3, 7, and 28days, the adjusted sequence ratios (aSRs) for all anti-allergics and the 4 categories were greater than 1. The 7-day aSRs were 2.12 (95% CI: 2.08-2.15), 1.70 (95% CI: 1.68-1.73), 3.85 (95% confidence interval [CI]: 3.75-2.30), 2.30 (95% CI: 2.26-2.35), and 1.95 (95% CI: 1.89-2.02), respectively. The proportions of adverse drug events indicated by each signal were as follows: all anti-allergics (2.92%-3%), calcium gluconate (0.19%-0.52%), adrenergic/dopaminergic agents (2.20%-3.37%), glucocorticoids (3.13%-3.76%), and antihistamines (1.05%-1.32%). This first multi-center Chinese inpatient database study detected iodixanol-induced allergy signals, revealing that reactions may be much higher than those in collected spontaneous reports. Iodixanol risk exposure was closer to actual pharmaceutical care findings. PSSA application with ≤7-day intervals appears better suited for monitoring late allergic reaction signals with these drugs.

Prescription Sequence Symmetry Analysis (PSSA) to assess prescribing cascades: a step-by-step guide

Prescribing cascades occur when patients are prescribed medication to treat the adverse drug reaction of previously prescribed medication. Prescription sequence symmetry analysis (PSSA) can be used to assess the association between two medications in prescription or dispensing databases and thus the potential occurrence of prescribing cascades. In this article, a step-by-step guide is presented for conducting PSSA to assess prescribing cascades. We describe considerations for medication data collection and setting time periods for relevant parameters, including washout window, exposure window, continued exposure interval and blackout period. With two examples, we illustrate the impact of changes in these parameters on the strengths of associations observed. Given the impact seen, we recommend that researchers clearly specify and explain all considerations regarding medication included and time windows set when studying prescribing cascades with PSSA, and conduct subgroup and sensitivity analyses.

Association between Incidence of Prescriptions for Alzheimer's Disease and Beta-Adrenoceptor Antagonists: A Prescription Sequence Symmetry Analysis.

Alzheimer's disease (AD) is the most common cause of dementia, with a growing number of patients worldwide. The association between AD and treatment with drugs targeting the beta-adrenergic receptor is controversial. The aim of this study is to assess the association between the initiation of AD medication and beta-adrenoceptor antagonists (beta-blockers) in adults. We conducted a prescription sequence symmetry analysis using the University of Groningen IADB.nl prescription database. We determined the order of the first prescription for treating AD and the first prescription for beta-blockers, with the dispensing date of the first prescription for AD defined as the index date. Participants were adults over 45 years old starting any AD medication and beta-blockers within two years. We calculated adjusted sequence ratios with corresponding 95% confidence intervals. We identified 510 users of both AD and beta-blockers, and 145 participants were eligible. The results were compatible with either a significant decrease in the incidence of AD after using beta-blockers (adjusted sequence ratio (aSR) = 0.52; 95% CI: 0.35-0.72) or, conversely, an increase in beta-blockers after AD medication (aSR = 1.96; 95% CI: 1.61-2.30). There is a relationship between the use of beta-blockers and AD medications. Further research is needed with larger populations to determine whether drug therapy for AD increases the risk of hypertension or whether beta-blockers have potential protective properties against AD development.

Determining the effect of pneumococcal vaccination on antibiotic prescriptions: is prescription sequence symmetry analysis a valid approach?

Determining the effect of pneumococcal vaccination on antibiotic prescriptions: is prescription sequence symmetry analysis a valid approach?

Assessing prescription of antibiotics after vaccination against pneumococcal pneumonia; using prescription sequence symmetry analysis

ObjectivesPrescription sequence symmetry analysis (PSSA) is used to detect adverse event signals using administrative claims databases. In this study, we investigated whether PSSA can be applied to gauge the effects of PCV13 vaccination on antibiotic prescription rates in elderly patients. MethodsWe studied prescription records of patients aged 65 or older between 1 January 2014 and 31 December 2020, from the Helsana Swiss claims database. PSSA was performed to explore the relationship between 13-valent pneumococcal conjugate vaccine (PCV13) and six antibiotics recommended by the Swiss Society of Infectious Diseases for community-acquired pneumonia treatment (amoxicillin-clavulanate, azithromycin, clarithromycin, doxycycline, levofloxacin, and moxifloxacin), three additional antibiotics (amoxicillin, ciprofloxacin, and fosfomycin), and ten control drugs. ResultsAmoxicillin-clavulanate, clarithromycin, and levofloxacin were more likely to be prescribed before than after vaccination, for all time windows between 25 and 104 weeks. Adjusted sequence ratio (ASR) values ranged from 0.599 to 0.614, 0.508 to 0.568, and 0.514 to 0.752, respectively. Lower prescription rates after vaccination were also observed for azithromycin (all time windows between 38 and 104 weeks, ASR 0.705–0.739) and moxifloxacin (all time windows between 52 and 104 weeks, ASR 0.658–0.772). PCV13 did not have statistically significant associations with doxycycline, amoxicillin, ciprofloxacin, fosfomycin, or any of the ten controls. DiscussionThe lower prescription rate of antibiotics for community-acquired pneumonia after vaccination could be attributed to a protective effect of PCV13. This novel application of PSSA can be used to compare the real-world impact of other vaccines on drug consumption.

Safety of butylphthalide and edaravone in patients with ischemic stroke: a multicenter real-world study.

Butylphthalide (NBP) and edaravone (EDV) injection are common acute ischemic stroke medications in China, but there is a lack of large real-world safety studies on them. This study aimed to determine the incidence of adverse events, detect relevant safety signals, and assess the risk factors associated with these medications in real-world populations. In this study, data of acute ischemic stroke patients were extracted from the electronic medical record database of six tertiary hospitals between January 2019 and August 2021. Baseline confounders were eliminated using propensity score matching. The drugs' safety was estimated by comparing the results of 24 laboratory tests standards on liver function, kidney function, lipid level, and coagulation function. The drugs' relative risk was estimated by logistic regression. A third group with patients who did not receive NBP or EDV was constructed as a reference. Prescription sequence symmetry analysis was used to evaluate the associations between adverse events and NBP and EDV, respectively. 81,292 patients were included in this study. After propensity score matching, the NBP, EDV, and third groups with 727 patients in each group. Among the 15 test items, the incidence of adverse events was lower in the NBP group than in the EDV group, and the differences were statistically significant. The multivariate logistic regression equation revealed that NBP injection was not a promoting factor for abnormal laboratory test results, whereas EDV had statistically significant effects on aspartate transaminase, low-density lipoprotein cholesterol and total cholesterol. Prescription sequence symmetry analysis showed that NBP had a weak correlation with abnormal platelet count. EDV had a positive signal associated with abnormal results in gamma-glutamyl transferase, alanine aminotransferase, aspartate aminotransferase, prothrombin time, and platelet count. In a large real-world population, NBP has a lower incidence of adverse events and a better safety profile than EDV or other usual medications.

Continued potassium supplementation use following loop diuretic discontinuation in older adults: An evaluation of a prescribing cascade relic.

The use of a new medication (e.g., potassium supplementation) for managing a drug-induced adverse event (e.g., loop diuretic-induced hypokalemia) constitutes a prescribing cascade. However, loop diuretics are often stopped while potassium may be unnecessarily continued (i.e., relic). We aimed to quantify the occurrence of relics using older adults previously experiencing a loop diuretic-potassium prescribing cascade as an example. We conducted a prescription sequence symmetry analysis using the population-based Medicare Fee-For-Service data (2011-2018) and partitioned the 150 days following potassium initiation by day to assess the daily treatment scenarios (i.e., loop diuretics alone, potassium alone, combination of loop diuretics and potassium, or neither). We calculated the proportion of patients developing the relic, proportion of person-days under potassium alone, the daily probability of the relic, and the proportion of patients filling potassium after loop diuretic discontinuation. We also identified the risk factors of the relic. We identified 284,369 loop diuretic initiators who were 8 times more likely to receive potassium supplementation simultaneously or after (i.e., the prescribing cascade), rather than before, loop diuretic initiation (aSR 8.0, 95% CI 7.9-8.2). Among the 66,451 loop diuretic initiators who subsequently (≤30 days) initiated potassium, 20,445 (30.8%) patients remained on potassium after loop diuretic discontinuation, and 9365 (14.1%) patients subsequently filled another potassium supplementation. Following loop diuretic initiation, 4.0% of person-days were for potassium alone, and daily probability of the relic was the highest after day 90 of loop diuretic initiation (5.6%). Older age, female sex, higher diuretic daily dose, and greater baseline comorbidities were risk factors for the relic, while patients having the same prescriber or pharmacy involved in the use of both medications were less likely to experience the relic. Our findings suggest the need for clinicians to be aware of the potential of relic to avoid unnecessary drug use.

Evaluating the use of prescription sequence symmetry analysis as a pharmacovigilance tool: A scoping review.

The (prescription) sequence symmetry analysis (PSSA) design has been used to identify potential prescribing cascade signals by assessing the prescribing sequence of an index drug relative to a marker drug presumed to treat an adverse drug event provoked by the index drug. This review aimed to explore the use of the PSSA design as a pharmacovigilance tool with a particular focus on the breadth of identified signals and advances in PSSA methodology. We searched Embase, PubMed/Medline, Google Scholar, Web of Science and grey literature to identify studies that used the PSSA methodology. Two reviewers independently extracted relevant data for each included article. Study characteristics including signals identified, exposure time window, stratified analyses, and use of controls were extracted. We identified 53 studies which reported original results obtained using PSSA methodology or quantified the validity of components of the PSSA design. Of those, nine studies provided validation metrics showing reasonable sensitivity and high specificity of PSSA to identify prescribing cascade signals. We identified 340 unique index drug - marker drug signals published in the PSSA literature, representing 281 unique index - marker pharmacological class dyads (i.e., unique fourth-level Anatomical Therapeutic Chemical [ATC] classification dyads). Commonly observed signals were identified for index drugs acting upon the nervous system (34%), cardiovascular system (21%), and blood and blood-forming organs (15%), and many marker drugs were related to the nervous system (25%), alimentary tract and metabolism (23%), cardiovascular system (17%), and genitourinary system and sex hormones (14%). Negative controls and positive controls were utilized in 21% and 13% of studies, respectively. The PSSA methodology has been used in 53 studies worldwide to detect and evaluate over 300 unique prescribing cascades signals. Researchers should consider sensitivity analyses incorporating negative and/or positive controls and additional time windows to evaluate time-varying biases when designing PSSA studies.

Detecting Suspected Prescribing Cascades by Prescription Sequence Symmetry Analysis of Nationwide Real-World Data

A prescription cascade is a subsequent event that occurs when an adverse drug event is misinterpreted as a new medical condition, resulting in the prescription of a potentially unnecessary medication to treat this new condition. This study was designed to test the hypothesis of whether prescribing cascades exist and their magnitude among older individuals by using prescription sequence symmetry analysis (PSSA). A retrospective population-based cohort study based on data from Taiwan's National Health Insurance Research Database (NHIRD), a nationwide claims-based database that covers 99% of the population in Taiwan. Patients receiving newly initiated index and marker drugs in the outpatient setting between 2014 and 2016 were included. Those who received index and marker drugs on the same date were excluded. PSSA measures the propensity for a marker drug (eg, thyroxine) to be prescribed after an index drug (eg, amiodarone) has been initiated, where the index drug is suspected of inducing a side effect (eg, hypothyroidism) and the marker drug is used to treat the side effect. We evaluated 14 PSSA sets as potential prescription cascade-related drug pairs (index and marker drug), including 2 confirmatory analyses (eg, amiodarone and thyroxin), to check the validity of the PSSA results and 12 exploratory analyses of cardiovascular medication-related prescribing cascades (eg, statins and antidepressants). The observation periods for sequences of incident marker drug use were 1year before and 1year after the use of the incident index drug, and the symmetry of prescriptions filled for the 2 periods was examined. The results of the PSSA were performed as the crude sequence ratio (SR), defined as the ratio of patients initiating the marker drug after the index drug (causal group) to those initiating the marker drug before the index drug (noncausal group), and the adjusted SR (aSR) with 95% confidence intervals (CIs). Among 12 potential prescription cascade-related drug pairs in exploratory analysis, 9 of them reached statistical significance, and aSR ranged from 1.02 to 1.46. Dihydropyridine calcium channel blocker-induced edema showed the highest aSR (1.46, 95% CI 1.45-1.48), and statin-induced muscle pain showed the lowest aSR (1.02, 95% CI 1.02-1.03). Our study supported the application of PSSA in detecting prescribing cascades using a nationwide claims database. Nevertheless, most previously reported prescribing cascades among cardiovascular medications were shown to have a low effect size of sequence ratios among older individuals.

Evaluation of a Beta-Blocker-Edema-Loop Diuretic Prescribing Cascade: A Prescription Sequence Symmetry Analysis.

Drug-related adverse events associated with antihypertensive therapy may result in subsequent prescribing of other potentially harmful medications, known as prescribing cascades. The aim of this study was to assess the magnitude and characteristics of a beta-blocker-edema-loop diuretic prescribing cascade. A prescription sequence symmetry analysis was used to assess loop diuretic initiation before and after initiation of beta-blockers among patients 20 years or older without heart failure, atrial fibrillation, other arrythmias, or use of calcium channel blocker within a U.S. private insurance claims database (2005-2018). The temporality of loop diuretic initiation relative to a beta-blocker or negative control (renin-angiotensin system blocker) initiation was tabulated. Secular trend-adjusted sequence ratios (aSRs) with 95% confidence intervals (CIs) compared the initiation of loop diuretic 90 days before and after initiation of beta-blockers. Among 988,675 beta-blocker initiators, 9,489 patients initiated a new loop diuretic prescription 90 days after and 5,245 patients before beta-blocker initiation, resulting in an aSR of 1.78 (95% CI, 1.72-1.84). An estimated 1.72 beta-blocker initiators per 100 patient-years experienced the prescribing cascade in the first 90 days. The aSR was disproportionately higher among older adults (aSR 1.97), men (aSR 2.25), and patients who initiated metoprolol tartrate (aSR 2.48), labetalol (aSR 2.18), or metoprolol succinate (aSR 2.11). Negative control results (aSR 1.09, 95% CI, 1.05-1.13) generally corroborated our findings, but suggested modest within-person time-varying confounding. We observed excess use of loop diuretics following beta-blocker initiation that was only partially explained by secular trends or hypertension progression.

Pharmacovigilance of traditional Chinese medicine: an exploration based on prescription sequence analysis and prescription sequence symmetry analysis

Multiple methods should be incorporated into the research on pharmacovigilance of traditional Chinese medicine(TCM for a comprehensive and objective evaluation. The arrival of the era of medical big data allows it to be deeply integrated into medical research. The real world study(RWS) represented by hospital information system(HIS) provides a data basis for exploring the pharmacovigilance of TCM. Prescription sequence analysis(PSA) and prescription sequence symmetry analysis(PSSA) developed based on the former serve as a methodological basis for clinical safety evaluation of Chinese patent medicines after marketing. By collating the related studies of HIS, PSA and PSSA and employing the propensity score matching( PSM) method and nested case-control study(NCCS), this paper formed a HIS-, PSA-and PSSA-based technical system for clinical safety evaluation of Chinese patent medicines in the real world, in order to provide a methodological demonstration for the future research on the pharmacovigilance of TCM.

Evaluation of the key prescription sequence symmetry analysis assumption using the calcium channel blocker: Loop diuretic prescribing cascade.

To evaluate the prescription sequence symmetry analysis assumption regarding balance between marker drug (i.e., medication used to treat a drug-induced adverse event) initiation rates before and after initiation of an index drug (i.e., medication that is potentially associated with the drug-induced adverse event) in the absence of prescribing cascades, we used a well-described example of loop diuretic initiation to treat dihydropyridine calcium channel blockers (DH CCB)-induced edema. The University of Florida Health Integrated Data Repository from June 2011 and July 2018 was used to assess temporal prescribing of DH CCB and loop diuretics within the prescription sequence symmetry analysis framework. Validation of the prescribing cascade was performed via clinical expert chart review. Among patients without heart failure who were initiated on DH CCB, 26 and 64 loop diuretics initiators started within 360 days before versus after DH CCB initiation, respectively, resulting in an adjusted sequence ratio (aSR) of 2.27 (95% CI, 1.44-3.58). Overall, 35 (54.7%) patients were determined to have a prescribing cascade. Removing patients who experienced a prescribing cascade resulted in an aSR of 1.05, 95% CI 0.62-1.78). Loop diuretic initiation rates before and after DH CCB initiation for reasons other a prescribing cascade were similar, thus confirming the prescription sequence symmetry analysis assumption.

Prescription sequence symmetry analysis in pharmacoepidemiology: a systematic review

Objective: To systematically evaluate and analyze the original research of prescription sequence symmetry analysis (PSSA), summarize its research progress and methodological details, and provide a reference for the future use of this method. Methods: The keywords related to PSSA were used for literature retrieval from Chinese databases (CNKI, Wanfang, and VIP) and English databases (PubMed, Embase, and Cochrane). Original articles that were related to PSSA and published before June 30, 2020 were selected. Information form was developed by Excel. Stata was used for the statistics analysis. Results: There were 45 eligible articles included in the research. Since 2013, the number of studies using PSSA has increased rapidly. These studies were mainly conducted in Japan (n=11, 24.44%), China (n=10, 22.22%), Denmark (n=9, 20.00%), and Australia (n=8, 17.78%). Medical claim database was used most commonly when PSSA was implemented. The included studies involved 16 types of drugs, of which the number of studies of psychotropic drugs and statins was highest (n=8, 17.78%), and adverse reactions of almost all human systems were involved. In terms of methodology, 35 (77.78%) and 43 (95.56%) studies clearly reported the run-in period and interval period, of which 14 (31.11%) and 9 (20.00%) respectively gave the method or reason for determining the duration. In addition, 16 articles (35.56%) and 18 articles (40.00%) reported sensitivity analysis and subgroup analysis results, respectively. Conclusions: PSSA, one of the effective methods for safety signal detection in healthcare databases, has developed rapidly, but the methodological details and result reporting need to be improved. In China, PSSA research is still in its infancy, and it is necessary to pay attention to the quality of research and promote methodological exploration.

Use of negative controls in a prescription sequence symmetry analysis to reduce time‐varying bias

There is an increased use in the (prescription) sequence symmetry analysis (PSSA); however, limited studies have incorporated a negative control, and no study has formally quantified and controlled for within-patient time-varying bias using a negative control. Our aim was to develop a process to incorporate the effect of negative controls into the main analysis of a PSSA. Using a previously assessed dihydropyridine calcium channel blocker (DH-CCB) and loop diuretic PSSA, we directly compared the adjusted sequence ratios (aSRs) of DH-CCBs to each of the two negative control index drugs (levothyroxine and angiotensin converting enzyme [ACE] inhibitor/angiotensin-2 receptor blocker [ARB]) using the ratio of the aSRs to estimate a relative aSR with a Z test. Further, we utilized the relative aSR in stratum-specific analyses and varying exposure windows. The relative aSR of DH-CCBs decreased from 1.87 to 1.72 (95% CI 1.66-1.78) using levothyroxine as a negative control index drug. ACE inhibitor/ARB negative control index drug resulted in an aSR of 1.27 thus reducing the relative aSR for DH-CBB from 1.84 to 1.45 (95% CI 1.41-1.49). When restricting the exposure window to 180 and 90 days, the relative aSR of DH-CCBs increased to 1.68 (95% CI 1.62-1.74) and 1.86 (95% CI 1.78-1.94), respectively, relative to the ACE inhibitor/ARB negative control index drug. We illustrated how to incorporate negative control index drugs into a PSSA and generate relative aSRs. Stratum-specific assessments and varying the exposure windows while using negative control index drugs can yield more informative results.

Risk of Liver Injury Associated with Intravenous Lipid Emulsions: A Prescription Sequence Symmetry Analysis.

Aims: To determine the risk of liver injury associated with the use of different intravenous lipid emulsions (LEs) in large populations in a real-world setting in China. Methods: A prescription sequence symmetry analysis was performed using data from 2015 Chinese Basic Health Insurance for Urban Employees. Patients newly prescribed both intravenous LEs and hepatic protectors within time windows of 7, 14, 28, 42, and 60 days of each other were included. The washout period was set to one month according to the waiting-time distribution. After adjusting prescribing time trends, we quantify the deviation from symmetry of patients initiating LEs first and those initiating hepatic protectors first, by calculating adjusted sequence ratios (ASRs) and relevant 95% confidence intervals. Analyses were further stratified by age, gender, and different generations of LEs developed. Results: In total, 416, 997, 1,697, 2,072, and 2,342 patients filled their first prescriptions with both drugs within 7, 14, 28, 42, and 60 days, respectively. Significantly increased risks of liver injury were found across all time windows, and the strongest effect was observed in the first 2 weeks [ASR 6.97 (5.77–8.42) ∼ 7.87 (6.04–10.61)] in overall patients. In subgroup analyses, female gender, age more than 60 years, and soybean oil-based and alternative-LEs showed higher ASRs in almost all time windows. Specially, a lower risk for liver injury was observed in the first 14 days following FO-LEs administration (ASR, 3.42; 95% CI, 0.81–14.47), but the risk started to rise in longer time windows. Conclusion: A strong association was found between LEs use and liver injury through prescription sequence symmetry analysis in a real-world setting, which aligns with trial evidence and clinical experience. Differences revealed in the risks of liver injury among various LEs need further evaluation.

Prescription sequence symmetry analysis for signal detection

Prescription sequence symmetry analysis for signal detection

Detecting Medicine Safety Signals Using Prescription Sequence Symmetry Analysis of a National Prescribing Data Set.

Medicine safety signal detection methods employed by the medicine regulator in Australia (Therapeutic Goods Administration [TGA], Department of Health) rely predominantly on analysis of spontaneous adverse event (AE) reports, sponsor notifications or information shared by international agencies. The limitations of these methods and the availability of large administrative health data sets has given rise to greater interest in the use of administrative health data to support pharmacovigilance (PV). We explored whether prescription sequence symmetry analysis (PSSA) of Pharmaceutical Benefits Scheme (PBS) data can enhance signal detection by the TGA, using the AE, heart failure (HF) as a case study. We applied the PSSA method to all single-ingredient medicines dispensed under the PBS between 2012 and 2016, using furosemide initiation as a proxy for new-onset HF. A signal was considered present if the lower limit of the 95% confidence interval for the adjusted sequence ratio was > 1. We excluded medicines known to cause HF, indicated for HF treatment or indicated for diseases that may contribute to HF. Of the 654 tested medicines, 26 potential new HF signals were detected by PSSA. Five signals had additional support for the possible association provided by biological plausibility, consistency and disproportionate reporting of cases of HF to the TGA and the World Health Organization; and clinical impact. PSSA was able to identify potential signals for further evaluation. With the increasing availability of different administrative health data sources, the strengths and weaknesses of methods used to analyse these data for the purpose of regulatory PV should be evaluated.