To test or to not test: A retrospective cross-sectional study on potentially inappropriate use of pathology testing in South Australian hospitals.

OBJECTIVES: To measure rates of potentially inappropriate pathology testing in the hospital setting. METHODS: Retrospective cross-sectional study in hospital setting from July 2021 to December 2021. We examined 3 potentially inappropriate uses: overordering, selection errors, and unnecessary repeat testing. Overordering included vitamin D and lipids (rarely required in acute hospital care). Selection error was the ratio of iron studies to standalone ferritin requests. Unnecessary repeats included any repeat vitamin D, lipids, iron, or ferritin in an episode of care or C-reactive protein (CRP) repeated within 3 days and N-terminal pro-brain natriuretic peptide (NT-proBNP) within 7 days and repeated previously abnormal CRP and NT-proBNP tests. Costs of inappropriate tests were estimated using the Australian Medicare Benefits Schedules. RESULTS: Among 55,904 test requests, 15% (n = 8120) were potentially inappropriate. Vitamin D was frequently ordered (n = 4498), as were lipids (n = 2872). Ratio of iron studies to standalone ferritin was 36. Of 19,233 repeat CRPs, 36% (n = 6947) were within 3 days and 62% (n = 179) of repeat NT-proBNPs were within 7 days of the first test. For initially abnormal tests, 89% of CRPs and 97% of NT-proBNPs remained abnormal. Inappropriate test costs accounted for 12% to 30% of costs. CONCLUSIONS: Frequent potential inappropriate use and selection of pathology tests was observed in South Australian hospitals.

Pioglitazone use in Australia and the United Kingdom following drug safety advisories on bladder cancer risk: An interrupted time series study.

PURPOSE: National regulators in Australia and the United Kingdom issued safety advisories on the association between pioglitazone use and bladder cancer in July 2011. The Australian advisory noted that males were at higher risk of bladder cancer than females, while the UK advisory highlighted a new recommendation, suggest careful consideration in the elderly due to increasing risk with age. This study examined whether these differences in the advisories had different age- and sex-based impacts in each country. METHODS: Interrupted time series analysis was used to compare pioglitazone use (prescriptions/100000 population) in Australia and the United Kingdom for the 24 months before and 11 months after the July 2011 safety advisories (study period July 2009-June 2012). Separate models were used to compare use by sex and age group (≥65 years vs. <65 years) in each country. RESULTS: Pioglitazone use fell in Australia (17%) and the United Kingdom (24%) following the safety advisories. Use of pioglitazone fell more for males (18%) than females (16%) in Australia, and more for females (25%) than males (23%) in the United Kingdom; however, neither difference was statistically significant (Australia p = 0.445, United Kingdom p = 0.462). Pioglitazone use fell to a similar extent among older people than younger people in the United Kingdom (23% vs. 26%, p = 0.354), and did not differ between age groups in Australia (both 18%, p = 0.772). CONCLUSIONS: The results indicate that differences in the Australian and UK safety advisories resulted in substantial reductions in pioglitazone use at the population level in both countries, however, differences by sub-groups were not observed.

The Risk of Preoperative Central Nervous System-Acting Medications on Delirium Following Hip or Knee Surgery: A Matched Case-Control Study.

INTRODUCTION: Medicines acting on the central nervous system can increase the risk of postoperative delirium, but the specific medicines associated with greatest risk remain unclear. OBJECTIVES: We aimed to examine the risk of individual central nervous system-acting medicines used preoperatively on delirium after hip or knee surgery. METHODS: A matched case-control study was conducted using data from the Australian Government Department of Veterans' Affairs. We included people aged 65 years or older who had knee or hip surgery between 2000 and 2019. People with hip or knee surgery who developed postoperative delirium were cases and controls were people with hip or knee surgery but who did not develop postoperative delirium. Use of medicines including anxiolytics, sedatives, and hypnotics, opioid analgesics and antidepressants prior to surgery was compared between cases and controls. RESULTS: A total of 2614 patient cases with postoperative delirium were matched by same sex, age (±2 years), and year of admission (±2 years) with 7842 controls without postoperative delirium. Cases were more likely to be exposed to nitrazepam (odds ratio [OR] = 1.81, 95% confidence interval [CI] 1.24-2.64), sertraline (OR = 1.50, 95% CI 1.20-1.87), mirtazapine (OR = 1.38, 95% CI 1.11-1.74), venlafaxine (OR = 1.42, 95% CI 1.02-1.98), citalopram (OR = 1.54, 95% CI 1.19-1.99), escitalopram (OR = 1.42, 95% CI 1.06-1.89) or fluvoxamine (OR = 5.01, 95% CI 2.15-11.68) prior to surgery than controls. At the class level, exposure to benzodiazepines (OR = 1.20, 95% CI 1.05-1.37) and antidepressants (OR = 1.64, 95% CI 1.47-1.83) prior to surgery was significantly higher in cases than in controls. The numbers needed to treat to harm for one additional delirium case were 43 for sertraline, 40 for citalopram, 57 for mirtazapine and 26 for nitrazepam. Whereas, the numbers needed to treat to harm were found to be 20 for sertraline, 17 for citalopram, 19 for mirtazapine and 10 for nitrazepam in the 85 years or older age group, indicating that the harmful effect of these medicines is pronounced as age advances. CONCLUSIONS: People who developed delirium following hip or knee surgery were more likely to be exposed to nitrazepam, sertraline, mirtazapine, venlafaxine, citalopram, escitalopram or fluvoxamine at the time of admission for surgery. Planning to reduce use of these medicines well prior to surgery may decrease the risk of postoperative delirium.

Cardiac Implantable Electronic Devices: Reoperations and the Competing Risk of Death.

BACKGROUND: The use of cardiac implantable electronic devices (CIED), which includes pacemakers, implantable cardioverter-defibrillators (ICD), cardiac resynchronisation therapy pacemakers (CRT-P) and cardiac resynchronisation therapy defibrillators (CRT-D) has increased over the past 20 years, but there is a lack of real world evidence on the longevity of these devices in the older population which is essential to inform health care delivery and support clinical decisions. METHODS AND RESULTS: We conducted a retrospective cohort study using data from the Australian Government Department of Veterans' Affairs database. The cohort consisted of people who had a CIED procedure between 2005 and 2015. The cumulative risk of generator replacement/reoperations was estimated accounting for the competing risk of death. A total of 16,662 patients were included. In pacemaker recipients with an average age of 85 years, the 5-year risk of reoperation ranged from 2.8% in single chamber, 3.6% in dual chamber to 7.6% in CRT-P recipients, while the 5-year risk of dying with the index pacemaker in situ was 63% in single chamber, 46% in dual chamber and 56% in CRT-P recipients. In defibrillator recipients with an average age of 80 years, the 5-year risk of reoperation ranged from 11% in single chamber, 13% in dual chamber to 24% in CRT-D recipients, while the 5-year risk of dying with the index defibrillator in situ was 46% in single chamber, 40% in dual chamber and 41% in CRT-D recipients. CONCLUSION: In this cohort of older patients the 5-year risk of generator reoperation was low in pacemaker recipients whereas up to one in four CRT-D recipients would have a reoperation within 5 years.

Risk of chronic opioid use in older persons with pre-existing anxiety.

OBJECTIVE: Work that has shown a relationship between anxiety and chronic opioid use has not focused on older people specifically, despite the additional risks in older populations. This study aimed to understand whether anxiety prior to opioid initiation increased the likelihood of chronic opioid use over time in persons aged 60 years or older. DESIGN: Administrative claims data were used to calculate time between initiation of opioids and a first chronic episode of opioid use. Patients were classified as having a history of anxiety if they were dispensed medicines in the anxiolytics class or had a hospitalization event for anxiety prior to treatment with an opioid. Proportional hazards models were used to compare the likelihood of experiencing a chronic episode of opioid use between those with and without a history of anxiety. RESULTS: The cohort was 15,000 persons, of which, 5,076 (34 percent) had history of anxiety. Those with anxiety prior to their first opioid dispensing were 30 percent more likely to have an episode of chronic use after adjustment for age, gender, number of comorbidities, and prior surgery (HR = 1.30, 95% CI = 1.16-1.47). The risk of a chronic episode in patients who had surgery prior to initiation of an opioid was 60 percent greater in those with anxiety compared to no anxiety (HR = 1.60, 95% CI = 1.21-2.11) and 24 percent greater in those with anxiety but no prior surgery (HR = 1.24, 95% CI = 1.08-1.42). CONCLUSIONS: A significant proportion of older people will have a chronic episode of opioid use. This risk is increased where a history of anxiety is present.

Mesh use in urogynaecological procedures between 2005 and 2016: An Australian cohort study.

BACKGROUND: Pelvic organ prolapse (POP) and stress urinary incontinence (SUI) are common conditions. The use of mesh in the surgical treatment of these conditions in Australia is unclear. AIM: To examine the use of mesh in POP and SUI procedures in an Australian national cohort of older women. METHODS: We conducted a population-based cohort study using data from the Australian Government Department of Veterans' Affairs (DVA) database. The cohort consisted of older women who had POP and SUI procedures between 1 July, 2005 and 31 December, 2016. Women who received mesh were identified by matching device billing codes with the Australian Government's Prosthesis List. RESULTS: In total, 3129 women experienced 3472 hospitalisations for POP and SUI procedures, with 74% of the women aged 75 years and older. There were 2276 (66%) hospitalisations with single POP repairs, 608 (18%) with single SUI procedures and 588 (17%) with concomitant POP and SUI procedures. Mesh was used in 23% of single procedures for POP, in 89% of single procedures for SUI and in 90% of concomitant POP and SUI procedures. The use of mesh in POP procedures decreased from a peak of 33% in 2008 down to 8% by 2016, whereas the use of mesh in SUI procedures increased from 77% in 2006 to 91% by 2016. CONCLUSION: Mesh was commonly used in SUI procedures, whereas use of mesh in POP repair was less common and the use decreased rapidly after 2011, when warnings about use of mesh in POP were first issued.

Using Post-market Utilisation Analysis to Support Medicines Pricing Policy: An Australian Case Study of Aflibercept and Ranibizumab Use.

OBJECTIVES: To describe how post-market utilisation analysis in Australia informs cost-effectiveness assessment and pricing decisions, using aflibercept and ranibizumab as case studies. METHODS: Pharmaceutical claims were used to identify initiators of aflibercept and ranibizumab in the year after aflibercept-listing (December 2012), and ranibizumab initiators in the year before aflibercept listing. The dispensing rates for each cohort were calculated, and their demographic and clinical characteristics compared using Kruskal-Wallis tests. RESULTS: Aflibercept and ranibizumab each accounted for half the age-related macular degeneration market following aflibercept listing. Aflibercept initiators had similar dispensing rates to ranibizumab initiators in the pre- and post-aflibercept era (~ three scripts during the first 90 days, and eight to nine scripts during the following 12 months). All cohorts were similar in terms of their age, sex, residential aged-care status and geographic remoteness, and no differences were observed in their overall co-morbidity scores and history of thromboembolic events. CONCLUSIONS: Contrary to clinical trial protocols, post-market utilisation research for ranibizumab and aflibercept demonstrates equivalent use in practice in terms of dose frequency, and the demographic and clinical characteristics of initiators. This supports Australia's decision to pay the same price for each rather than giving a premium to aflibercept. Many other countries are likely overpaying for aflibercept if their utilization patterns are similar to Australia's, and could benefit from incorporating routine utilisation assessment.

Prior experience with cardiovascular medicines predicted longer persistence in people initiated to combinations of antihypertensive and lipid-lowering therapies: findings from two Australian cohorts.

PURPOSE: Many studies of persistence involving fixed dose combinations (FDCs) of cardiovascular medicines have not adequately accounted for a user's prior experience with similar medicines. The aim of this research was to assess the effect of prior medicine experience on persistence to combination therapy. PATIENTS AND METHODS: Two retrospective cohort studies were conducted in the complete Pharmaceutical Benefits Scheme prescription claims dataset. Initiation and cessation rates were determined for combinations of: ezetimibe/statin; and amlodipine/statin. Initiators to combinations of these medicines between April and September 2013 were classified according to prescriptions dispensed in the prior 12 months as either: experienced to statin or calcium channel blocker (CCB); or naïve to both classes of medicines. Cohorts were stratified according to formulation initiated: FDC or separate pill combinations (SPC). Cessation of therapy over 12 months was determined using Kaplan-Meier survival analysis. Risk of cessation, adjusted for differences in patient characteristics was assessed using Cox proportional hazard models. RESULTS: There were 12,169 people who initiated combinations of ezetimibe/statin; and 26,848 initiated combinations of amlodipine/statin. A significant proportion of each cohort were naïve initiators: ezetimibe/statin cohort, 1,964 (16.1%) of whom 81.9% initiated a FDC; and amlodipine/statin cohort, 5,022 (18.7%) of whom 55.4% initiated a FDC. Naïve initiators had a significantly higher risk of ceasing therapy than experienced initiators regardless of formulation initiated: ezetimibe/statin cohort, naïve FDC versus experienced FDC HR=3.0 (95% CI 2.8, 3.3) and naïve SPC versus experienced SPC HR=4.4 (95% CI 3.8, 5.2); and amlodipine/statin cohort naïve FDC versus experienced FDC HR=2.0 (95% CI 1.8, 2.2) and naïve SPC versus experienced SPC HR=1.5 (95% CI 1.4, 1.6). CONCLUSION: Prescribers are initiating people to combinations of two cardiovascular medicines without prior experience to at least one medicine in the combination. This is associated with a higher risk of ceasing therapy than when combination therapy is initiated following experience with one component medicine. The use of FDC products does not overcome this risk.

Persistent Opioid Use Following Total Knee Arthroplasty: A Signal for Close Surveillance.

BACKGROUND: Prolonged opioid use following total knee arthroplasty (TKA) has not been extensively studied. METHODS: A cohort study of primary TKA for osteoarthritis using an integrated healthcare system and Total Joint Replacement Registry (January 2008-December 2011) was conducted. Opioid use during the first year after TKA was the exposure of interest and cumulative daily oral morphine equivalent (OME) amounts were calculated. Total postsurgical OME per 90-day exposure periods were categorized into quartiles. The end point was aseptic revision surgery. Survival analyses were conducted and hazard ratios (HRs) were adjusted for age, gender, prior analgesic use, opioid-related comorbidities, and chronic pain diagnoses. RESULTS: A total of 24,105 patients were studied. After the initial 90-day postoperative period, 41.5% (N = 9914) continued to use opioids. Also, 155 (0.6%) revisions occurred within 1 year and 377 (1.6%) within 5 years. Compared to patients not taking any opioids, patients using medium-low to high OME after the initial 90-day period had a higher adjusted risk of 1-year revision, ranging from HR = 2.4 (95% confidence interval, 1.3-4.5) to HR = 33 (95% confidence interval, 10-110) depending on the OME and time period. CONCLUSION: Patients who require opioids beyond 90 days after TKA warrant close follow-up.

Antipsychotic polypharmacy in older Australians.

ABSTRACTBackground:Antipsychotics are commonly used, and the rate of use is highest, among those aged 65 years or over, where the risk of adverse events is also high. Up to 20% of younger adults use more than one antipsychotic concurrently; however there are few studies on the prevalence of antipsychotic polypharmacy in older people. We aimed to analyze antipsychotic use in elderly Australians, focusing on the prevalence of antipsychotic polypharmacy and the use of medicines to manage adverse events associated with antipsychotics. METHODS: A cross-sectional study was conducted using Australian Department of Veterans' Affairs (DVA) administrative claims data for the period 1 March 2014 to 30 June 2014. Veterans dispensed at least one antipsychotic medicine during the study period was included. We determined the number of participants dispensed antipsychotic polypharmacy and the number of participants dispensed medicines to manage antipsychotic side effects. RESULTS: There were 7,412 participants with a median age of 86 years. Fifty-one percent (n=3,784) were women and 48% (n=3,569) lived in residential aged-care. Fifty one participants (0.7%) were dispensed anticholinergic medicines indicated for the management of antipsychotic-associated extrapyramidal movement disorders and eight (0.1%) were dispensed medicines for the management of hyperprolactinemia. Five percent of participants (n=365) received dual antipsychotics. Dual antipsychotic users were more likely to be under the care of a psychiatrist or to have had a mental health hospitalization than those using a single antipsychotic. CONCLUSIONS: Antipsychotic polypharmacy occurred in one in 20 elderly persons, indicating that there is room for improvement in antipsychotic use in elderly patients.

Preoperative medication use and postoperative delirium: a systematic review.

BACKGROUND: Medications are frequently reported as both predisposing factors and inducers of delirium. This review evaluated the available evidence and determined the magnitude of risk of postoperative delirium associated with preoperative medication use. METHODS: A systematic search in Medline and EMBASE was conducted using MeSH terms and keywords for postoperative delirium and medication. Studies which included patients 18 years and older who underwent major surgery were included. The methodological quality of included studies was assessed independently by two authors using the Newcastle-Ottawa quality assessment scale for cohort studies. RESULTS: Twenty-nine studies; 25 prospective cohort, three retrospective cohort and one post hoc analysis of RCT data were included. Only four specifically aimed to assess medicines as an independent predictor of delirium, all other studies included medicines among a number of potential predictors of delirium. Of the studies specifically testing the association with a medication class, preoperative use of beta-blockers (OR = 2.06[1.18-3.60]) in vascular surgery and benzodiazepines RR 2.10 (1.23-3.59) prior to orthopedic surgery were significant. However, evidence is from single studies only. Where medicines were included as one possible factor among many, hypnotics had a similar risk estimate to the benzodiazepine study, with one significant and one non-significant result. Nifedipine use prior to cardiac surgery was found to be significantly associated with delirium. The non-specific grouping of psychoactive medication use preoperatively was generally higher with an associated two-to-seven-fold higher risk of postoperative delirium, while only two studies included narcotics without other agents, with one significant and one non-significant result. CONCLUSIONS: There was a limited number of high quality studies in the literature quantifying the direct association between preoperative medication use and postsurgical delirium. More studies are required to evaluate the association of specific preoperative medications on the risk of postoperative delirium so that comprehensive guidelines for medicine use prior to surgery can be developed to aid delirium prevention. TRIAL REGISTRATION: This systematic review has been registered on PROSPERO International prospective register of systematic reviews (Registration number: CRD42016051245 ).

Chronic Use of Opioids Before and After Total Knee Arthroplasty: A Retrospective Cohort Study.

BACKGROUND: Opioids are commonly used for the management of preoperative and postoperative pain among patients undergoing total knee arthroplasty (TKA). There is limited literature on the chronic use of opioids pre-TKA and post-TKA. The aim of this study was to characterize the use of opioids in TKA patients before and after surgery and identify risk factors of chronic opioid use. METHODS: Opioid use among 15,020 patients undergoing TKA (01/01/2001-31/12/2012) was examined. Generalized estimating equations assessed change in total oral morphine equivalents pre-TKA and post-TKA, and logistic regression estimated risk factors of chronic opioid use. RESULTS: Of the total sample, 7782 (52.0%) patients had at least 1 opioid (38.6% pre-TKA and 34.4% post-TKA). The most commonly prescribed opioids were oxycodone, codeine + acetaminophen, and tramadol. Pre-TKA, 720 (4.8%) patients were chronic opioid users, of which 241 (33.5%) stopped being chronic users after surgery and 479 (66.5%) continued but had a 16% reduction (incidence rate ratio = 0.84; 95% confidence interval, 0.78-0.90) in total oral morphine equivalents. Of the 5077 (33.8%) occasional opioid user pre-TKA, 2407 (47.4%) stopped after surgery. Compared to nonopioid users, chronic users were younger, were female, had more comorbidity, and had longer hospital stays. Older age was associated with ceasing chronic opioid use post-TKA. CONCLUSION: There was a reduction in opioid use following TKA. Almost 50% of occasional users and more than 30% of chronic users pre-TKA ceased opioids postoperatively. There was a reduction in use for those chronic users who continued to take opioids postsurgery.

Switching between endocrine therapies for primary breast cancer: Frequency and timing in Australian clinical practice.

AIMS: To determine the frequency, timing and patterns of endocrine therapy switching in Australian practice for postmenopausal women with primary breast cancer. METHODS: We identified postmenopausal women in a population-based cohort commencing endocrine therapy for invasive primary breast cancer between December 2005 and December 2008 (n = 645). Individual-level administrative health records and self-report data were used to determine women's demographic and clinical characteristics, including preexisting and newly-treated comorbidities, and switches in endocrine therapy. Time to therapy switching was calculated. Chi-square tests compared the characteristics of women who did and did not switch, and those switching within 2 years or after 2 years of commencing therapy. RESULTS: Twenty-eight percent of women switched from their initial endocrine therapy, most commonly from tamoxifen to anastrozole, or the converse. A small number of anastrozole-to-exemestane and letrozole-to-exemestane switches were observed (n = 19). Most women (>80%) who switched therapies did not have newly-treated comorbidities. Few women (<5%) switched before completing 2 years of therapy, but these women were significantly more likely to have preexisting antidepressant use than women switching later (43% vs 23%, P = 0.048) and remained on the subsequent therapy for less time (6 months vs 2.7 years, P < 0.001). CONCLUSIONS: Approximately one-quarter of postmenopausal women with primary breast cancer switched endocrine therapies. The findings suggest that the majority of switching in Australian practice was planned; occurring after 2-3 years of, not precipitated by comorbidity, and in a sequence supported by trial evidence. Early switching, however, was associated with preexisting depression and appeared to be a marker of poor persistence.

Postoperative opioid use as an early indication of total hip arthroplasty failure.

Background and purpose - A criticism of total hip arthroplasty (THA) survivorship analysis is that revisions are a late and rare outcome. We investigated whether prolonged opioid use is a possible indicator of early THA failure. Patients and methods - We conducted a cohort study of THAs registered in a total joint replacement registry from January 2008 to December 2011. 12,859 patients were evaluated. The median age was 67 years and 58% were women. Opioid use in the year after surgery was the exposure of interest, and the cumulative daily amounts of oral morphine equivalents (OMEs) were calculated. Post-THA OMEs per 90 day periods were categorized into quartiles. The endpoints were 1- and 5-year revisions. Results - After the first 90 days, 27% continued to use opioids. The revision rate was 0.9% within a year and 1.7% within 5 years. Use of medium-low (100-219 mg), medium-high (220-533 mg), and high (≥ 534 mg) amounts of OMEs in days 91-180 after surgery was associated with a 6 times (95% confidence interval (CI): 3-15), 5 times (CI: 2-13), and 11 times (CI: 2.9-44) higher adjusted risk of 1 year revision, respectively. The use of medium-low and medium-high amounts of OMEs in days 181-270 after surgery was associated with a 17 times (CI: 6-44) and 14 times (95% CI: 4-46) higher adjusted risk of 1-year revision. There was a similar higher risk of 5-year revision. Interpretation - Persistent postoperative use of opioids was associated with revision THA surgery in this cohort, and it may be an early indicator of potential surgical failures.

Risk factors for persistent and new chronic opioid use in patients undergoing total hip arthroplasty: a retrospective cohort study.

OBJECTIVES: To determine chronic opioid use pre-THA (total hip arthroplasty) and post-THA, and risk factors for persistent or new chronic opioid use post-THA. DESIGN: Retrospective cohort study. SETTING: Australian Government Department of Veterans' Affairs health claims database. PARTICIPANTS: 9525 patients who had an elective unilateral THA between 1/01/2001 and 12/31/2012. PRIMARY OUTCOME MEASURE: Chronic opioid use. Defined as 90 days of continuous opioid use or 120 days of non-continuous use. RESULTS: Pre-THA, 6.2% (n=593) of patients were chronic users, while 5.2% (n=492) were post-THA. Among the 492 postoperative chronic users, 302 (61%) were chronic users pre-THA and post-THA and 190 (39%) became new chronic users after surgery. Risk factors for persistent chronic use were younger age (OR=0.96, 95% CI 0.93 to 0.99/1-year increment), back pain (OR=1.99, 95% CI 1.20 to 3.23), diabetes (OR=3.52, 95% CI 1.05 to 11.8), hypnotics use (OR=2.52, 95% CI 1.48 to 4.30) and higher pre-THA opioid exposure (compared with opioid use for 94-157 days, 157-224 days (OR=3.75, 95% CI 2.28 to 6.18), 225+ days (OR=5.18, 95% CI 2.92 to 9.19). Risk factors for new chronic opioid use post-THA were being a woman (OR=1.40, 95% CI 1.00 to 1.96), back pain (OR=3.90, 95% CI 2.85 to 5.33), depression (OR=1.70, 95% CI 1.20 to 2.41), gastric acid disease (OR=1.62, 95% CI 1.16 to 2.25), migraine (OR=5.11, 95% CI 1.08 to 24.18), liver disease (OR=4.33, 95% CI 1.08 to 17.35), weight loss (OR=2.60, 95% CI 1.06 to 6.39), dementia (OR=2.19, 95% CI 1.04 to 4.61), hyperlipidaemia (OR=1.38, 95% CI 1.00 to 1.91), hypnotics (OR=1.56, 95% CI 1.13 to 2.16) and antineuropathic pain medication use (OR=3.11, 95% CI 2.05 to 4.72). CONCLUSIONS: Patients undergoing THA are exposed to opioids for long periods of time, putting them at high risk of harm related to opioid use. We identified groups at risk of chronic opioid use, including younger patients and women, as well as modifiable risk factors of chronic opioid use, including level of opioid exposure presurgery and hypnotic use. These indicators of chronic opioid use can be used by clinicians to target patient groups for suitable pain management interventions.

Opioid use after total hip arthroplasty surgery is associated with revision surgery.

BACKGROUND: Pain is an indication for total hip arthroplasty (THA) and it should be resolved post-surgery. Because patients' pain is typically treated pharmacologically we tested whether opioid use can be used as a surrogate for patient-reported pain and as an indicator for early surgical failure. Specifically, we evaluated whether the amount of opioids taken within the year after THA was associated with one and five years risk of revision surgery. METHODS: A cohort of 9943 THAs (01/2001-12/2012) was evaluated. Post-operative opioid use was the exposure of interest and cumulative daily oral morphine equivalent (OME) amounts were calculated. Total OMEs/90-day periods were categorised into quartiles. Revisions within one and five years were the outcomes of interest. RESULTS: Of the THAs, 2.0 % (N = 200) were revised within one year and 4.2 % (N = 413) within five years. After adjustments for gender, age, surgical indication, co-morbidities, and other analgesics, revision was associated with amount of OMEs in the second quarter after THA (days 91-180 after discharge). Patients on medium-high amounts of OME (400-1119 mg) had higher risk of one (hazard ratio (HR) = 2.22, 95 % CI 1.08-4.56) and five year (HR = 1.66, 95 % CI 1.08-2.56) revision than a patient not taking opioids. During the same period, patients taking the highest amounts of OMEs (≥1120 mg) had a 2.64 (95 % CI 1.03-6.74) times higher risk of one year and a 2.11 (95 % CI 1.13-3.96) times higher risk of five year revision. CONCLUSIONS: Opioid use 91-180 days post-surgery is associated with higher risk of revision surgery and therefore is an early and useful indicator for surgical failure.

Using Medications for Prediction of Revision after Total Joint Arthroplasty.

This study evaluated the ability of a pharmacy based co-morbidity measure (RxRisk-V) to predict odds of one and five years revision in total hip arthroplasty (THA) and total knee arthroplasty (TKA) and compared its performance to the more commonly used co-morbidity measures in orthopaedics (Charlson and Elixhauser). 11,848 patients with THAs and 18,972 with TKAs performed between 2001 and 2012 were evaluated. Using a combination of conditions, identified by both the pharmacy and diagnoses based coding algorithms, models with acceptable predictive ability of THA and TKA revision were developed. These findings suggest prescription based co-morbidity measures can positively contribute to case-mix adjustment and outcome prediction in this patient population.

Brief Report: Databases in the Asia-Pacific Region: The Potential for a Distributed Network Approach.

BACKGROUND: This study describes the availability and characteristics of databases in Asian-Pacific countries and assesses the feasibility of a distributed network approach in the region. METHODS: A web-based survey was conducted among investigators using healthcare databases in the Asia-Pacific countries. Potential survey participants were identified through the Asian Pharmacoepidemiology Network. RESULTS: Investigators from a total of 11 databases participated in the survey. Database sources included four nationwide claims databases from Japan, South Korea, and Taiwan; two nationwide electronic health records from Hong Kong and Singapore; a regional electronic health record from western China; two electronic health records from Thailand; and cancer and stroke registries from Taiwan. CONCLUSIONS: We identified 11 databases with capabilities for distributed network approaches. Many country-specific coding systems and terminologies have been already converted to international coding systems. The harmonization of health expenditure data is a major obstacle for future investigations attempting to evaluate issues related to medical costs.

Predicting Infections After Total Joint Arthroplasty Using a Prescription Based Comorbidity Measure.

This study evaluated the association and predictive ability of co-morbidities measured by RxRisk-V, Elixhauser and Charlson measures and post-total hip (THA) and total knee arthroplasties (TKA) infection. THAs and TKAs (2001-2012) were identified using the Australian Department of Veterans' Affairs data. Infections within 90 days post-surgery were the study endpoint. Co-morbidities were identified using pharmacy (RxRisk-V) and hospitalization history (Elixhauser, Charlson). Of the 11,848 THAs, 3.1% (N = 364) had infections and out of 18,972 TKAs 3.4% (N = 648). Comorbidity burden and specific conditions were associated with infection likelihood. RxRisk-V performed better than other measures, but none had high predictive ability and differences were small. The best performing infection prediction models resulted when a combination of conditions identified by all measures was used.

Reducing inappropriate polypharmacy: the process of deprescribing.

Inappropriate polypharmacy, especially in older people, imposes a substantial burden of adverse drug events, ill health, disability, hospitalization, and even death. The single most important predictor of inappropriate prescribing and risk of adverse drug events in older patients is the number of prescribed drugs. Deprescribing is the process of tapering or stopping drugs, aimed at minimizing polypharmacy and improving patient outcomes. Evidence of efficacy for deprescribing is emerging from randomized trials and observational studies. A deprescribing protocol is proposed comprising 5 steps: (1) ascertain all drugs the patient is currently taking and the reasons for each one; (2) consider overall risk of drug-induced harm in individual patients in determining the required intensity of deprescribing intervention; (3) assess each drug in regard to its current or future benefit potential compared with current or future harm or burden potential; (4) prioritize drugs for discontinuation that have the lowest benefit-harm ratio and lowest likelihood of adverse withdrawal reactions or disease rebound syndromes; and (5) implement a discontinuation regimen and monitor patients closely for improvement in outcomes or onset of adverse effects. Whereas patient and prescriber barriers to deprescribing exist, resources and strategies are available that facilitate deliberate yet judicious deprescribing and deserve wider application.