Algorithmic approach to finding people with multiple sclerosis using routine healthcare data in Wales.

BACKGROUND: Identification of multiple sclerosis (MS) cases in routine healthcare data repositories remains challenging. MS can have a protracted diagnostic process and is rarely identified as a primary reason for admission to the hospital. Difficulties in identification are compounded in systems that do not include insurance or payer information concerning drug treatments or non-notifiable disease. AIM: To develop an algorithm to reliably identify MS cases within a national health data bank. METHOD: Retrospective analysis of the Secure Anonymised Information Linkage (SAIL) databank was used to identify MS cases using a novel algorithm. Sensitivity and specificity were tested using two existing independent MS datasets, one clinically validated and population-based and a second from a self-registered MS national registry. RESULTS: From 4 757 428 records, the algorithm identified 6194 living cases of MS within Wales on 31 December 2020 (prevalence 221.65 (95% CI 216.17 to 227.24) per 100 000). Case-finding sensitivity and specificity were 96.8% and 99.9% for the clinically validated population-based cohort and sensitivity was 96.7% for the self-declared registry population. DISCUSSION: The algorithm successfully identified MS cases within the SAIL databank with high sensitivity and specificity, verified by two independent populations and has important utility in large-scale epidemiological studies of MS.

Risk factors for HIV infection overlooked in routine antenatal care.

We have ascertained the extent to which risk factors for HIV infection may escape detection by standard history-taking procedures in an antenatal clinic. This study was based on 1264 women from a multi-ethnic population in an inner London health district (City and Hackney). All had agreed to undergo attributable HIV testing and a detailed personal interview. Thirty-nine per cent (494 of 1264 women) reported risk factors contributed personally or by a partner. Most of these risk factors had not been earlier disclosed by routine history taking. In most cases the risk was residence and risk activity in a World Health Organization (WHO) Pattern 2 country. [HIV spread WHO categories: Pattern 1--principally homosexual/bisexual males and i.v. drug use (areas = North America, Western Europe, Australasia, parts of South America) with male to female ratio 10/1; Pattern 2--Heterosexual (areas = Sub Saharan Africa, Caribbean and part South America) with male to female 1/1.] Thirty-one subjects (2.4%) were aware that their partners had participated in bisexual activity. Only six subjects perceived themselves at risk through their own or partner's drug injecting activity. The frequency of risk factors was substantially greater than that ascertained by the routine history. The findings highlight the potential risk of heterosexual spread resulting from travel to or residence in high prevalence territories. The contribution by male partners is significant and is particularly difficult to detect during a routine interview. These data support the recommendation that voluntary HIV serum testing should be universal rather than a selective offer based on risk factors determined at a routine history.

Antenatal testing for HIV antibody: problems of documentation and record.

The objective of this study was to audit an ante-natal HIV screening programme by observing the congruence of documentation of consent between case notes and request forms; correlation of testing with prior agreement to be tested; and recording documentation that the test had been offered but declined in women who were not tested. The design was one of retrospective case note review of 538 women drawn from an inner city teaching hospital. There was documentation of invitation to undergo HIV testing in 415 (77%) cases. Test documentation was absent in 123 (23%) cases which represent 37% of those for whom a test was not performed. HIV testing was performed in 205 (38%) cases. There was discrepancy between documentation of consent to testing on the laboratory request form and in the notes. Some blood specimens of women agreeing to be tested were apparently never received in the laboratory. Incomplete documentation and a low test uptake suggests a low acceptance. However, without adequate documentation it cannot be determined in those not tested whether the test was declined or whether the invitation was either never extended, or not implemented after acceptance. Audit of implementation and staff compliance should be established at the outset of any universal testing programme.

Evaluation of an antenatal HIV testing programme in an inner London health district.

OBJECTIVE: To study an antenatal human immunodeficiency virus (HIV) testing programme in an inner London health district. DESIGN: A standardised research interview was given to women in the first half of pregnancy and the findings were compared with those of the routine clinical interview. The observations were analysed in relation to the results of HIV antibody testing, either attributable by consent or anonymously, in these women. SETTING: The Homerton Hospital, London. SUBJECTS: Three thousand seven hundred and twenty-nine women, of whom 1696 (45.5%) consented to testing. RESULTS: Four women who had consented to testing had a positive result. Amongst the 2,033 women (54.5%) who declined the test, four (or five) had a positive result. The number of risk factors ascertained by the research study interview was substantially greater than that elicited by the preceding routine interview. In addition, more information was obtained by a routine computer interview than by its unstructured equivalent. There was no obvious association between the presence of a risk factor and whether or not the women had consented to the test. CONCLUSIONS: Our formal voluntary testing programme detected nearly 44% of HIV seropositive individuals. Thus, there were four known positives during the study period against a total of nine detected by anonymous testing. Since all the known positive results in the study were associated with recognised risk factors, there is some doubt as to the value of a universal testing programme. However, if testing is to be based upon the existence of a risk factor elicited at the booking history, then the deficiencies in this history revealed by the present study need to be corrected.

Risk identification for HIV infection in an inner London antenatal population.

This study was carried out to ascertain whether routine antenatal history taking is an effective means of identifying risk factors for HIV infection. Information about risk obtained at routine booking was compared with answers to selected questions obtained at a research interview. The study was conducted at St. Bartholomew's Hospital Homerton, and ran from February 1991 to March 1992. Of the 3729 women interviewed, 1671 had been hand booked (unstructured questionnaire) and 2058 had been computer booked (structured questionnaire). Hand booking failed to identify 77% of risk factors compared with 7% for computer booking. The findings highlight the underdetection of risk activity and confirm the need for intermittent, anonymous sampling to obtain background information against which a decision to implement universal testing may be made.