Identifying complications of interventional procedures from UK routine healthcare databases: a systematic search for methods using clinical codes

Feasibility analysis of conducting observational studies with the electronic health record

Background

The secondary use of electronic health records (EHRs) promises to facilitate medical research. We reviewed general data requirements in observational studies and analyzed the feasibility of conducting observational studies with structured EHR data, in particular diagnosis and procedure codes.

Methods

After reviewing published observational studies from the University Hospital of Erlangen for general data requirements, we identified three different study populations for the feasibility analysis with eligibility criteria from three exemplary observational studies. For each study population, we evaluated the availability of relevant patient characteristics in our EHR, including outcome and exposure variables. To assess data quality, we computed distributions of relevant patient characteristics from the available structured EHR data and compared them to those of the original studies. We implemented computed phenotypes for patient characteristics where necessary. In random samples, we evaluated how well structured patient characteristics agreed with a gold standard from manually interpreted free texts. We categorized our findings using the four data quality dimensions “completeness”, “correctness”, “currency” and “granularity”.

Results

Reviewing general data requirements, we found that some investigators supplement routine data with questionnaires, interviews and follow-up examinations. We included 847 subjects in the feasibility analysis (Study 1 n = 411, Study 2 n = 423, Study 3 n = 13). All eligibility criteria from two studies were available in structured data, while one study required computed phenotypes in eligibility criteria. In one study, we found that all necessary patient characteristics were documented at least once in either structured or unstructured data. In another study, all exposure and outcome variables were available in structured data, while in the other one unstructured data had to be consulted. The comparison of patient characteristics distributions, as computed from structured data, with those from the original study yielded similar distributions as well as indications of underreporting. We observed violations in all four data quality dimensions.

Conclusions

While we found relevant patient characteristics available in structured EHR data, data quality problems may entail that it remains a case-by-case decision whether diagnosis and procedure codes are sufficient to underpin observational studies. Free-text data or subsequently supplementary study data may be important to complement a comprehensive patient history.

Long-term Rate of Mesh Sling Removal Following Midurethral Mesh Sling Insertion Among Women With Stress Urinary Incontinence

Importance

There is concern about outcomes of midurethral mesh sling insertion for women with stress urinary incontinence. However, there is little evidence on long-term outcomes.

Objective

To examine long-term mesh removal and reoperation rates in women who had a midurethral mesh sling insertion for stress urinary incontinence.

Design, Setting, and Participants

This population-based retrospective cohort study included 95 057 women aged 18 years or older who had a first-ever midurethral mesh sling insertion for stress urinary incontinence in the National Health Service hospitals in England between April 1, 2006, and December 31, 2015. Women were followed up until April 1, 2016.

Exposures

Patient and hospital factors and retropubic or transobturator mesh sling insertions.

Main Outcomes and Measures

The primary outcome was the risk of midurethral mesh sling removal (partial or total) and secondary outcomes were reoperation for stress urinary incontinence and any reoperation including mesh removal, calculated with death as competing risk. A multivariable Fine-Gray model was used to calculate subdistribution hazard ratios as estimates of relative risk.

Results

The study population consisted of 95 057 women (median age, 51 years; interquartile range, 44-61 years) with first midurethral mesh sling insertion, including 60 194 with retropubic insertion and 34 863 with transobturator insertion. The median follow-up time was 5.5 years (interquartile range, 3.2-7.5 years). The rate of midurethral mesh sling removal was 1.4% (95% CI, 1.3%-1.4%) at 1 year, 2.7% (95% CI, 2.6%-2.8%) at 5 years, and 3.3% (95% CI, 3.2%-3.4%) at 9 years. Risk of removal declined with age. The 9-year removal risk after transobturator insertion (2.7% [95% CI, 2.4%-2.9%]) was lower than the risk after retropubic insertion (3.6% [95% CI, 3.5%-3.8%]; subdistribution hazard ratio, 0.72 [95% CI, 0.62-0.84]). The rate of reoperation for stress urinary incontinence was 1.3% (95% CI, 1.3%-1.4%) at 1 year, 3.5% (95% CI, 3.4%-3.6%) at 5 years, and 4.5% (95% CI, 4.3%-4.7%) at 9 years. The rate of any reoperation, including mesh removal, was 2.6% (95% CI, 2.5%-2.7%) at 1 year, 5.5% (95% CI, 5.4%-5.7%) at 5 years, and 6.9% (95% CI, 6.7%-7.1%) at 9 years.

Conclusions and Relevance

Among women undergoing midurethral mesh sling insertion, the rate of mesh sling removal at 9 years was estimated as 3.3%. These findings may guide women and their surgeons when making decisions about surgical treatment of stress urinary incontinence.

Complications following vaginal mesh procedures for stress urinary incontinence: an 8 year study of 92,246 women

Complications of surgical mesh procedures have led to legal cases against manufacturers worldwide and to national inquiries about their safety. The aim of this study was to investigate the rate of adverse events of these procedures for stress urinary incontinence in England over 8 years. This was a retrospective cohort study of first-time tension-free vaginal tape (TVT), trans-obturator tape (TOT) or suprapubic sling (SS) surgical mesh procedures between April 2007 and March 2015. Cases were identified from the Hospital Episode Statistics database. Outcomes included number and type of procedures, including those potentially confounded by concomitant procedures, and frequency, nature and timing of complications. 92,246 first-time surgical mesh procedures (56,648 TVT, 34,704 TOT, 834 SS and 60 combinations) were identified, including 68,002 unconfounded procedures. Peri-procedural and 30-day complication rates in the unconfounded cohort were 2.4 [2.3–2.5]% and 1.7 [1.6–1.8]% respectively; 5.9 [5.7–6.1]% were readmitted at least once within 5 years for further mesh intervention or symptoms of complications, the highest risk being within the first 2 years. Complication rates were higher in the potentially confounded cohort. The complication rate within 5 years of the mesh procedure was 9.8 [9.6:10.0]% This evidence can inform future decision-making on this procedure.

Estimating the incidence and the economic burden of third and fourth-degree obstetric tears in the English NHS: an observational study using propensity score matching

OBJECTIVE

Obstetric care is a high-risk area in healthcare delivery, so it is essential to have up-to-date quantitative evidence in this area to inform policy decisions regarding these services. In light of this, the objective of this study is to investigate the incidence and economic burden of third and fourth-degree lacerations in the English National Health Service (NHS) using recent national data.

METHODS

We used coded inpatient data from Hospital Episode Statistics (HES) for the financial years from 2010/2011 to 2013/2014 for all females that gave birth during that period in the English NHS. Using HES, we used pre-existing safety indicator algorithms to calculate the incidence of third and fourth-degree obstetric tears and employed a propensity score matching method to estimate the excess length of stay and economic burden associated with these events.

RESULTS

Observed rates per 1000 inpatient episodes in 2010/2011 and 2013/2014, respectively: Patient Safety Indicator-trauma during vaginal delivery with instrument (PSI 18)=84.16 and 91.24; trauma during vaginal delivery without instrument (PSI 19)=29.78 and 33.43; trauma during caesarean delivery (PSI 20)=3.61 and 4.56. Estimated overall (all PSIs) economic burden for 2010/2011=£10.7 million and for 2013/2014=£14.5 million, expressed in 2013/2014 prices.

CONCLUSIONS

Despite many initiatives targeting the quality of maternity care in the NHS, the incidence of third and fourth-degree lacerations has increased during the observed period which signals that quality improvement efforts in obstetric care may not be reducing incidence rates. Our conservative estimates of the financial burden of these events appear low relative to total NHS expenditure for these years.

Adverse events after first, single, mesh and non-mesh surgical procedures for stress urinary incontinence and pelvic organ prolapse in Scotland, 1997-2016: a population-based cohort study

BACKGROUND

Concerns have been raised about the safety of surgery for stress urinary incontinence and pelvic organ prolapse using transvaginal mesh. We assessed adverse outcomes after first, single mesh procedures and comparable non-mesh procedures.

METHODS

We did a cohort study of women in Scotland aged 20 years or older undergoing a first, single incontinence procedure or prolapse procedure during 1997-98 to 2015-16 identified from a national hospital admission database. Primary outcomes were immediate postoperative complications and subsequent (within 5 years) readmissions for later postoperative complications, further incontinence surgery, or further prolapse surgery. Poisson regression models were used to compare outcomes after procedures carried out with and without mesh.

FINDINGS

Between April 1, 1997, and March 31, 2016, 16 660 women underwent a first, single incontinence procedure, 13 133 (79%) of which used mesh. Compared with non-mesh open surgery (colposuspension), mesh procedures had a lower risk of immediate complications (adjusted relative risk [aRR] 0·44 [95% CI 0·36-0·55]) and subsequent prolapse surgery (adjusted incidence rate ratio [aIRR] 0·30 [0·24-0·39]), and a similar risk of further incontinence surgery (0·90 [0·73-1·11]) and later complications (1·12 [0·98-1·27]); all ratios are for retropubic mesh. During the same time period, 18 986 women underwent a first, single prolapse procedure, 1279 (7%) of which used mesh. Compared with non-mesh repair, mesh repair of anterior compartment prolapse was associated with a similar risk of immediate complications (aRR 0·93 [95% CI 0·49-1·79]); an increased risk of further incontinence (aIRR 3·20 [2·06-4·96]) and prolapse surgery (1·69 [1·29-2·20]); and a substantially increased risk of later complications (3·15 [2·46-4·04]). Compared with non-mesh repair, mesh repair of posterior compartment prolapse was associated with a similarly increased risk of repeat prolapse surgery and later complications. No difference in any outcome was observed between vaginal and, separately, abdominal mesh repair of vaginal vault prolapse compared with vaginal non-mesh repair.

INTERPRETATION

Our results support the use of mesh procedures for incontinence, although further research on longer term outcomes would be beneficial. Mesh procedures for anterior and posterior compartment prolapse cannot be recommended for primary prolapse repair. Both vaginal and abdominal mesh procedures for vaginal vault prolapse repair are associated with similar effectiveness and complication rates to non-mesh vaginal repair. These results therefore do not clearly favour any particular vault repair procedure.

FUNDING

None.

Quantifying severe urinary complications after radical prostatectomy: the development and validation of a surgical performance indicator using hospital administrative data

OBJECTIVES

To develop and validate a surgical performance indicator based on severe urinary complications that require an intervention within 2 years of radical prostatectomy (RP), identified in hospital administrative data.

PATIENTS AND METHODS

Men who underwent RP between 2008 and 2012 in England were identified using hospital administrative data. A transparent coding framework based on procedure codes was developed to identify severe urinary complications which were grouped into 'stricture', 'incontinence' and 'other'. Their validity as a performance indicator was assessed by evaluating the consistency with diagnosis codes and association with patient and surgical characteristics. Kaplan-Meier methods were used to assess time to first occurrence and multivariable logistic regression was used to estimate adjusted odds ratios (ORs) for patient and surgical characteristics.

RESULTS

A total of 17 299 men were included, of whom 2695 (15.6%) experienced at least one severe urinary complication within 2 years. High proportions of men with a complication had relevant diagnosis codes: 86% for strictures and 93% for incontinence. Urinary complications were more common in men from poorer socio-economic backgrounds (OR comparing lowest with highest quintile: 1.45; 95% confidence interval [CI] 1.26-1.67) and in those with prolonged length of hospital stay (OR 1.54, 95% CI 1.40-1.69), and were less common in men who underwent robot-assisted surgery (OR 0.65, 95% CI 0.58-0.74).

CONCLUSION

These results show that severe urinary complications identified in administrative data provide a medium-term performance indicator after RP. They can be used for research assessing outcomes of treatment methods and for service evaluation comparing performance of prostate cancer surgery providers.

Procedural and short-term safety of bronchial thermoplasty in clinical practice: evidence from a national registry and Hospital Episode Statistics

OBJECTIVE

Bronchial thermoplasty (BT) is a novel treatment for severe asthma. Its mode of action and ideal target patient group remain poorly defined, though clinical trials provided some evidence on efficacy and safety. This study presents procedural and short-term safety evidence from routine UK clinical practice.

METHODS

Patient characteristics and safety outcomes (procedural complications, 30-day readmission and accident and emergency (A&E) attendance, length of stay) were assessed using two independent data sources, the British Thoracic Society UK Difficult Asthma Registry (DAR) and Hospital Episodes Statistics (HES) database. A matched cohort (with records in both) was used to estimate safety outcome event rates and compare them with clinical trials.

RESULTS

Between June 2011 and January 2015, 215 procedure records (83 patients; 68 treated in England) were available from DAR and 203 (85 patients) from HES. 152 procedures matched (59 patients; 6 centres), and of these, 11.2% reported a procedural complication, 11.8% resulted in emergency respiratory readmission, 0.7% in respiratory A&E attendance within 30 days (20.4% had at least one event) and 46.1% involved a post-procedure stay. Compared with published clinical trials which found lower hospitalisation rates, BT patients in routine clinical practice were, on average, older, had worse baseline lung function and asthma quality of life.

CONCLUSIONS

A higher proportion of patients experienced adverse events compared with clinical trials. The greater severity of disease amongst patients treated in clinical practice may explain the observed rate of post-procedural stay and readmission. Study of long-term safety and efficacy requires continuing data collection.