Routine preoperative medical testing for cataract surgery

What is the aim of this review?
The aim of this Cochrane Review was to determine whether it is necessary to perform preoperative medical testing before cataract surgery.

Key messages
Preoperative medical testing did not reduce the risk of medical adverse events during or after cataract surgery when compared to selective or no testing.

What was studied in the review?
Cataract surgery is practiced widely, and substantial resources are being committed to increasing the cataract surgical rate in low- and middle-income countries. With the current volume of cataract surgery and future increases, it is critical to be able to optimize the safety, but also the cost-effectiveness of this procedure. Most cataracts are age-related, and therefore surgeries are performed on older individuals with other health and eye conditions. It is likely that preoperative medical testing will detect medical conditions, but it is questionable whether these conditions should preclude these individuals from cataract surgery or change their perioperative management.

What are the main results of the review?
We included three studies in this review. One study was from Canada and the USA, another from Brazil, and the third from Italy. These studies compared routine preoperative medical testing versus selective or no testing. Study participants were followed from one week to two months after surgery.

The review shows the following.

• Preoperative medical testing did not reduce the risk of medical adverse events during or after cataract surgery when compared to selective or no testing (high-certainty evidence). The three studies reported results for 21,531 total cataract surgeries with 707 total surgery-associated medical adverse events, including 61 hospitalizations and three deaths. Of the 707 medical adverse events reported, 353 occurred in the pre-testing group and 354 occurred in the no-testing group.
• No clear difference was observed for the occurrence of eye-related adverse events during or after surgery (moderate-certainty evidence).
• One study evaluated cost, estimating the cost to be 2.55 times higher in those who had routine preoperative medical testing compared to those who had selective preoperative testing (moderate-certainty evidence).
• There was no difference in the cancellation of surgery between those with routine preoperative medical testing and those with no or selective preoperative testing (high-certainty evidence).
• No study reported changes in surgical management (other than cancellation of surgery) or quality of life measures (evidence gaps).

How up-to-date is this review?
We searched for studies that had been published up to 29 June 2018.

Authors' conclusions: 

This review has shown that routine preoperative testing does not increase the safety of cataract surgery. Alternatives to routine preoperative medical testing have been proposed, including self administered health questionnaires, which could substitute for health provider histories and physical examinations. Such avenues may lead to cost-effective means of identifying those at increased risk of medical adverse events due to cataract surgery. However, despite the rare occurrence, adverse medical events precipitated by cataract surgery remain a concern because of the large number of elderly patients with multiple medical comorbidities who have cataract surgery in various settings. The studies summarized in this review should assist recommendations for the standard of care of cataract surgery, at least in low- and middle-income settings. Unfortunately, in these settings, medical history questionnaires may be useless to screen for risk because few people have ever been to a physician, let alone been diagnosed with any chronic disease.

Read the full abstract...
Background: 

Cataract surgery is practiced widely, and substantial resources are committed to an increasing cataract surgical rate in low- and middle-income countries. With the current volume of cataract surgery and future increases, it is critical to optimize the safety and cost-effectiveness of this procedure. Most cataracts are performed on older individuals with correspondingly high systemic and ocular comorbidities. It is likely that routine preoperative medical testing will detect medical conditions, but it is questionable whether these conditions should preclude individuals from cataract surgery or change their perioperative management.

Objectives: 

1. To investigate the evidence for reductions in adverse events through preoperative medical testing

2. To estimate the average cost of performing routine medical testing

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 6); Ovid MEDLINE; Embase.com; PubMed; LILACS BIREME, the metaRegister of Controlled Trials (mRCT) (last searched 5 January 2012); ClinicalTrials.gov and the WHO ICTRP. The date of the search was 29 June 2018, with the exception of mRCT which is no longer in service. We searched the references of reports from included studies for additional relevant studies without restrictions regarding language or date of publication.

Selection criteria: 

We included randomized clinical trials in which routine preoperative medical testing was compared to no preoperative or selective preoperative testing prior to age-related cataract surgery.

Data collection and analysis: 

Two review authors independently assessed abstracts to identify possible trials for inclusion. For each included study, two review authors independently documented study characteristics, extracted data, and assessed risk of bias.

Main results: 

We identified three randomized clinical trials that compared routine preoperative medical testing versus selective or no preoperative testing for 21,531 cataract surgeries. The largest trial, in which 19,557 surgeries were randomized, was conducted in Canada and the USA. Another study was conducted in Brazil and the third in Italy. Although the studies had some issues with respect to performance and detection bias due to lack of masking (high risk for one study, unclear for two studies), we assessed the studies as at overall low risk of bias.

The three randomized clinical trials included in this review reported results for 21,531 total cataract surgeries with 707 total surgery-associated medical adverse events, including 61 hospitalizations and three deaths. Of the 707 medical adverse events reported, 353 occurred in the pre-testing group and 354 occurred in the no-testing group (odds ratio (OR) 1.00, 95% confidence interval (CI) 0.86 to 1.16; high-certainty evidence). Most events were cardiovascular and occurred during the intraoperative period. Routine preoperative medical testing did not reduce the risk of intraoperative (OR 0.99, 95% CI 0.71 to 1.38) or postoperative ocular adverse events (OR 1.11, 95% CI 0.74 to 1.67) when compared to selective or no testing (2 studies; 2281 cataract surgeries; moderate-certainty evidence). One study evaluated cost savings, estimating the costs to be 2.55 times higher in those with preoperative medical testing compared to those without preoperative medical testing (1 study; 1005 cataract surgeries; moderate-certainty evidence). There was no difference in cancellation of surgery between those with preoperative medical testing and those with selective or no preoperative testing, reported by two studies with 20,582 cataract surgeries (OR 0.97, 95% CI 0.78 to 1.21; high-certainty evidence). No study reported outcomes related to clinical management changes (other than cancellation) or quality of life scores.

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