6 research outputs found
Evaluation of appendicitis risk prediction models in adults with suspected appendicitis
Background
Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis.
Methods
A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis).
Results
Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent).
Conclusion
Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified
Macroeconomic Policies and the Pakistan's Economy
For forecasting and policy analysis, large simultaneous
equation econometric models are routinely used today in many developing
countries. In the beginning there was growing enthusiasm about the
effectiveness and relevance of Keynesian Macroeconometric models.
However, the development of macroeconometric models with Rational
Expectations has created much suspicion regarding the validity ofthe a
priori restrictions [known as Lucas (1976) critique] used to identify
Keynesian macroeconometric models. The response to this. dissatisfaction
led to the development of macroeconometric models proposed by Sims
(1980, 1982 and 1986~ Doan, Litterman and Sims (1984) and Litterman
(1984), which use the modem time series techniques known as vector
autoregression (V AR) models. The V AR modelling avoids imposing
potentially spurious a priori restrictions on the model. In fact, the V
AR model does not require any explicit economic theory to estimate a
model. Moreover, it allows one to capture empirical regularities in the
data and thereby provide insight into channels through which the
different policy variables operates. Pakistan is relatively a latecomer
in the field of macro-models. The only large-scale model is the PIDE
Macroeconometric Model of 1983 which is a refinement of its earlier
version of 1982. This model consists of 33 behavioural and 25
definitional equations with 58 endogenous and 35 exogenous variables.
Almost all price variables are exogenous. The production and expenditure
block (the largest of the three blocks of the model), consisting of 34
equations is completely static. The use of a large number of exogenous
variables in the macroeconomic model has rendered the forecasting
capability seriously limited
Appendicitis risk prediction models in children presenting with right iliac fossa pain (RIFT study): a prospective, multicentre validation study.
Background
Acute appendicitis is the most common surgical emergency in children. Differentiation of acute appendicitis from conditions that do not require operative management can be challenging in children. This study aimed to identify the optimum risk prediction model to stratify acute appendicitis risk in children.
Methods
We did a rapid review to identify acute appendicitis risk prediction models. A prospective, multicentre cohort study was then done to evaluate performance of these models. Children (aged 5\u201315 years) presenting with acute right iliac fossa pain in the UK and Ireland were included. For each model, score cutoff thresholds were systematically varied to identify the best achievable specificity while maintaining a failure rate (ie, proportion of patients identified as low risk who had acute appendicitis) less than 5%. The normal appendicectomy rate was the proportion of resected appendixes found to be normal on histopathological examination.
Findings
15 risk prediction models were identified that could be assessed. The cohort study enrolled 1827 children from 139 centres, of whom 630 (34\ub75%) underwent appendicectomy. The normal appendicectomy rate was 15\ub79% (100 of 630 patients). The Shera score was the best performing model, with an area under the curve of 0\ub784 (95% CI 0\ub782\u20130\ub786). Applying score cutoffs of 3 points or lower for children aged 5\u201310 years and girls aged 11\u201315 years, and 2 points or lower for boys aged 11\u201315 years, the failure rate was 3\ub73% (95% CI 2\ub70\u20135\ub72; 18 of 539 patients), specificity was 44\ub73% (95% CI 41\ub74\u201347\ub72; 521 of 1176), and positive predictive value was 41\ub74% (38\ub75\u201344\ub74; 463 of 1118). Positive predictive value for the Shera score with a cutoff of 6 points or lower (72\ub76%, 67\ub74\u201377\ub74) was similar to that of ultrasound scan (75\ub70%, 65\ub73\u201383\ub71).
Interpretation
The Shera score has the potential to identify a large group of children at low risk of acute appendicitis who could be considered for early discharge. Risk scoring does not identify children who should proceed directly to surgery. Medium-risk and high-risk children should undergo routine preoperative ultrasound imaging by operators trained to assess for acute appendicitis, and MRI or low-dose CT if uncertainty remains.
Funding
None