Two approaches to linking census and hospital data

BACKGROUND

This study compares registry and non-registry approaches to linking 2006 Census of Population data for Manitoba and Ontario to hospital data from the Discharge Abstract Database (DAD).

DATA AND METHODS

Using a probabilistic linkage, the registry approach linked the census data to provincial health insurance registries, followed by a deterministic linkage to the DAD based on health insurance number (HIN). The non-registry approach used hierarchical deterministic exact matching based on three variables common to both files to link census data to the DAD. The approaches were compared in terms of linkage and coverage rates, sensitivity and specificity, and consistency of HINs on the linked records.

RESULTS

Results of the registry and non-registry linkage approaches were similar. In Manitoba, 7% and 6% of census long-form respondents linked to the DAD with the registry and non-registry linkage approaches, respectively; in Ontario, the linkage rate was 5% for both approaches. With the registry approach, the linked census-DAD data represented 84% (weighted) of hospital admissions in the 2006/2007 DAD in both provinces, compared with 82% in Manitoba and Ontario with the non-registry approach.

INTERPRETATION

In the absence of access to provincial health insurance registries with which census data can be linked, a non-registry approach can be used to create a research-quality dataset.

[Retrograde endopyelotomy using Holmium-Yag laser for uretero-pelvic junction obstruction]

OBJECTIVE

To evaluate our results of retrograde laser endopyelotomy for uretero-pelvic junction obstruction.

MATERIAL AND METHODS

Retrospective study of 27 consecutive retrograde laser endopyelotomies performed on 24 patients over a six years period (June 1999 to July 2005). Sixteen stenoses were primary. The level of obstruction was severe in 13 patients and moderate in 14 patients. A polar pedicle was diagnosed by pre-operative CT-angiography in seven cases. Balloon dilatation was performed in 17 procedures. A double J ureteral stent remained in place for six weeks mean. We evaluated results by a clinical examination and an excretory urography (at 1 and 6 months then annually). Mean follow-up was 35+/-22.7 months.

RESULTS

Mean operating time and mean length of hospital stay were 49.8+/-17.9min and four days (range: 2-10 days). Two cases of pyelonephritis were observed. The overall success was 70%. In the eight unresolved cases, the failure appeared at 2.7+/-1 month mean. Success criteria were moderate level of obstruction and primary junction. Here, patients so selected have 100% of success.

CONCLUSION

Study confirmed retrograde laser endopyelotomy was safety with a short length of hospital stay. This minimally invasive procedure should be reserved to primary moderate stenoses without polar pedicle.

Wireless telephones and the risk of road crashes

In light of the rapidly increasing development of the cell phone market, the use of such equipment while driving raises the question of whether it is associated with an increased accident risk; and if so, what is its magnitude. This research is an epidemiological study on two large cohorts, namely users and non-users of cell phones, with the objective of verifying whether an association exists between cell phone use and road crashes, separating those with injuries. The Société de l'Assurance Automobile du Québec (SAAQ) mailed a questionnaire and letter of consent to 175000 licence holders for passenger vehicles. The questionnaire asked about exposure to risk, driving habits, opinions about activities likely to be detrimental to driving and accidents within the last 24 months. For cell phone users, questions pertaining to the use of the telephone were added. We received 36078 completed questionnaires, with a signed letter of consent. Four wireless phone companies provided the files on cell phone activity, and the SAAQ the files for 4 years of drivers' records and police reports. The three data sources were merged using an anonymized identification number. The statistical methods include logistic-normal regression models to estimate the strength of the links between the explanatory variables and crashes. The relative risk of all accidents and of accidents with injuries is higher for users of cell phones than for non-users. The relative risks (RR) for injury collisions and also for all collisions is 38% higher for men and women cell phone users. These risks diminish to 1.1 for men and 1.2 for women if other variables, such as the kilometres driven and driving habits are incorporated into the models. Similar results hold for several sub-groups. The most significant finding is a dose-response relationship between the frequency of cell phone use, and crash risks. The adjusted relative risks for heavy users are at least two compared to those making minimal use of cell phones; the latter show similar collision rates as do the non-users.

[Melanoma of the iris and pregnancy]

Iris melanoma is a malignant melanocytic tumor, making up 1.2%-6.6% of uveal malignant melanomas. The growth of choroidal melanoma during pregnancy is described and a hormonal influence is suggested. We present a case of iris melanoma occurring during pregnancy. A 32-year-old woman, in the 28(th) week of her fifth pregnancy, was referred to the ophthalmologist with a 2-month history of blurred vision and pain in her left eye. The visual symptoms became progressively worse with decreasing vision. Her visual acuity was 20/70 in her left eye, with a temporal, pigmented, prominent iris mass extending into the trabecular meshwork and the corneal endothelium. Elsewhere other pigmented localizations were found in the iris and in the trabecular meshwork. There was secondary glaucoma with intraocular pressure of 36mmHg and C/D=0.9. The right eye was normal. A general physical examination found no pigmented lesions. Chest radiography and hepatic ultrasonography revealed no metastasis. The diagnosis of iris malignant melanoma was made from the diffuse involvement extending into the trabecular meshwork and the advanced secondary glaucoma; an enucleation was performed and histopathological examination confirmed the diagnosis of iris melanoma with involvement of the trabecular meshwork. The patient had no further problems (follow-up of 11 months). From this case report, we discuss the differential diagnosis of iris melanoma and the hormonal influence on its growth.

Procedural characteristics of primary coronary angioplasty in diabetic patients with acute anterior myocardial infarction

BACKGROUND

Mortality and morbidity rates are higher in diabetics compared to non-diabetics after acute myocardial infarction (AMI). Previous angiographic studies regarding primary angioplasty for the treatment of AMI found that angioplasty was similarly successful in diabetics and non-diabetics. However, it is noteworthy that patients of "real life" are often far from the population randomised in prospective protocols. The aim of this study was to examine the procedural characteristics of consecutive diabetic patients hospitalised for anterior AMI and treated with primary angioplasty as compared to non-diabetics.

METHOD

We analysed 28 consecutive diabetics and 74 non-diabetics who underwent primary angioplasty for anterior AMI (< 12 h from the onset of symptoms) during 15 consecutive months between 2000 and 2001 in our institution, depending on the presence or absence of diabetes.

RESULTS

Among analysed data, we found that in diabetics compared to non diabetics: (i) the delay before arrival in the cath-lab was significantly longer (5.5 +/- 2.7 vs 4.2 +/- 2.8 h); (ii) there was a less important collateral flow coming from the non-culprit arteries towards the culprit artery; (iii) there was a less important rate of recovery of a normal flow (TIMI 3) in the culprit artery after coronary angioplasty (67% vs 91%).

CONCLUSION

Our study demonstrates that several procedural characteristics could explain the poorer prognosis of AMI treated by primary angioplasty in the diabetic population. The longer delay found in diabetics before arrival in hospital could probably be improved.