In this article, Dr Solborg Bjerrum discusses his recent study assessing whether there is an increased risk of post-op endophthalmitis in private clinics versus public hospitals.
In Denmark, it is required by law that all public and private cataract surgery is registered in the National Patient Registry (NPR). By retrieving data on cataract surgery and PE from the NPR it is theoretically possible to conduct national surveillance of PE and to intervene if any public eye departments or private eye clinics perform cataract surgery with a risk of PE that is too high compared to what is expected. One of the downsides of using the NPR is that a few private eye clinics have made special agreements with local health authorities which mean that they are exempted from registration to the NPR. In these cases, the cataract operations must be registered in one of the two following registries: The National Health Insurance Service Registry (SSR) and the registry of Danish patients treated in foreign hospitals and activities in private specialist practice that are not settled by the health insurance agreement (DUSAS).
We discovered that one of the problems of using the NPR to study the risk of PE was that some of the cataract surgeries that led to PE were not registered in the NPR. Almost all public cataract surgery (98%) was in the NPR but only 38% of the private cataract operations that led to PE were registered in the NPR. The only reason why we could identify where the rest of these private operations were performed was because we manually evaluated the charts of the patients.
Looking only at the risk of PE after registered cataract surgery, we found that 39 cases of PE occurred after public cataract surgery; risk of PE = 0.36 per 1000 cataract operations and 27 cases of PE occurred after private cataract surgery; risk of PE = 0.73 per 1000 cataract operations. The risk of PE did not vary statistically significantly between the 7 public eye departments in our study and was similar to or lower than the risk of PE in comparable studies from other parts of Europe.4–6 During the study period, the risk of PE after public cataract surgery fell from 0.5 per 1000 cataract operations in the period 2002–2004 to 0.29 per 1000 cataract operations in the period 2008–2010.
Looking only at the risk of PE after surgery that was not registered in the NPR, we found that 2 private eye clinics were responsible for almost half of a total of 45 PE cases. These two clinics were also among the 6 private eye clinics that had a statistically significantly higher risk of PE compared to the public eye departments after cataract surgery that was registered in the NPR. We have later retrieved data on cataract surgery from SSR and DUSAS and discovered that 31 of the 45 PE cases (69%) that occurred after cataract surgery, which was not registered in the NPR, were not registered in SSR or DUSAS either. This indicates that much private cataract surgery is being performed in Denmark without being registered even though it is required by law as previously mentioned.
The risk of PE in Denmark at the public eye departments was low and comparable to the risk of PE from other parts of Europe. Most of the private eye clinics had a risk of PE that was lower or similar to the risk of PE at the public eye departments. However, cataract surgery at a few private eye clinics seemed to be associated with an increased risk of PE. The use of a registry such as the NPR is a cheap and effective method of monitoring complications to cataract surgery such as PE but at the moment the NPR is incomplete since many private cataract operations are not registered in the NPR. Many of these cataract operations are not registered in other registries either even though it is required by law. The Danish health authorities need to put more emphasis on the importance of these registrations in the future to ensure quality control of cataract surgery.
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