Background
Methods
Practice characteristics | All practices within the geographical areas covered by the sites (Cornwall, Newham and Kent) were eligible and were invited to participate in the trial by letter. |
Each practice that accepted the invitation to participate was allocated to an intervention or control group via a centrally-administered minimisation algorithm that aimed to ensure that the groups of practices were similar in terms of practice size, deprivation index, proportion of non-white patients, prevalence of diabetes, COPD and heart failure, and site (Cornwall, Kent and Newham). | |
Patient characteristics | Within each practice, patients aged 18 or over were deemed eligible on the basis of a diagnosis in primary or secondary care for COPD, heart failure or diabetes. |
Eligibility was not conferred on the basis of formal clinical assessment of disease severity. Instead patients were deemed eligible on the basis of either (i) their inclusion on the relevant Quality Outcomes Framework register in primary care, (ii) a confirmed medical diagnosis in primary or secondary care medical records as indicated by general practice Read Codes or ICD-10 codes, or (iii) confirmation of disease status by a local clinician (i.e. general practitioner or community matron) or by their hospital consultant. | |
Patients were not excluded on the basis of additional physical co-morbidities. However, the patient’s home had to be suitable for the installation of telehealth. |
Telehealth intervention
Data sets
Study cohort and end points
Statistical analysis
Unadjusted | The simplest models, although accounting for the effect of clustering, used no additional case-mix adjustment. |
Adjusted | These models additionally controlled for residual imbalances in a set of baseline characteristics. This set included age, sex, ethnicity, site, number of chronic health conditions, principal long-term condition (diabetes, chronic obstructive pulmonary disease or heart failure), an area-based socioeconomic deprivation score (national quartiles of the Index of Multiple Deprivation 2007), and a metric corresponding to the endpoint (e.g., general practitioners contacts) calculated over several periods within the two years prior to recruitment. |
The number of chronic health conditions was a count of diagnoses recorded on inpatient data over the three years prior to starting the trial. Principal long-term conditions were assigned using a pragmatic approach according to published criteria [16]. | |
Combined model | More complex case-mix adjustment was conducted using the Combined Predictive Model [16] a standard instrument designed to estimate the probability that an individual will experience an emergency hospital admission in a future twelve month period. The Combined Model score uses 72 variables covering age, sex, recorded health conditions, prior hospital use and prescribing, but not primary care contacts. These variables are sourced from general practice and hospital administrative data. Where a general practice did not grant approval to extract data for the evaluation, or where scores could not be calculated, scores were imputed for its patients based on the available information, which included age, sex and the hospital variables. Single imputation was used based on linear regression on the logit scale. When used in the case-mix adjustment, the Combined Predictive Model score was calculated for each participant at the end of the month prior to the start date. |
Results
Patient recruitment
Baseline differences
Control | Intervention | Standardised difference (%) | |
---|---|---|---|
Number in group | 1098 | 1219 | |
Number of practices | 80 | 82 | |
Number of patients per practice (median (range)) | 10 (1 to 62) | 8 (1 to 76) | |
Index long-term condition | |||
Chronic Obstructive Pulmonary Disease | 47.4 | 45.0 | −4.8 |
Diabetes | 22.6 | 27.1 | 10.4 |
Heart failure | 30.0 | 27.9 | −4.6 |
Number of chronic health conditions (mean (SD)) | 1.9 (1.8) | 1.8 (1.8) | −3.9 |
Site | |||
Cornwall | 32.6 | 36.5 | 8.2 |
Kent | 36.2 | 32.7 | −7.2 |
Newham | 31.2 | 30.8 | −1.0 |
Age (mean (SD)) | 70.8 (11.8) | 69.7 (11.6) | −9.3 |
Aged under 65 | 28.7 | 30.1 | 3.1 |
Aged 65-74 | 31.4 | 34.9 | 7.5 |
Aged 75-84 | 30.9 | 27.4 | −7.7 |
Aged 85+ | 9.0 | 7.5 | −5.3 |
Female (%) | 40.4 | 41.1 | 1.3 |
Ethnicity | |||
White | 71.3 | 71.8 | 1.0 |
Non-white | 13.2 | 12.3 | −2.7 |
Unknown | 15.5 | 15.9 | 1.2 |
Area-level deprivation (mean (SD))* | 29.8 (13.8) | 28.8 (14.9) | −6.9 |
1st quartile | 5.1 | 8.7 | 14.3 |
2nd quartile | 15.4 | 15.5 | 0.2 |
3rd quartile | 31.8 | 32.6 | 1.9 |
4th quartile | 47.7 | 43.2 | −9.2 |
GP visits per person (prior year) (mean (SD)) | 9.0 (7.6) | 8.8 (6.8) | −2.0 |
None | 4.5 | 3.5 | −4.8 |
1-5 | 35.2 | 33.1 | −4.6 |
6-10 | 29.0 | 30.5 | 3.4 |
11-20 | 23.2 | 26.4 | 7.4 |
>20 | 8.1 | 6.5 | −6.3 |
Practice nurse contacts per person (prior year) (mean (SD)) | 6.1 (8.1) | 5.3 (7.8) | −10.2 |
None | 14.8 | 15.5 | 2.1 |
1-5 | 51.1 | 57.1 | 12.1 |
6-10 | 16.4 | 14.8 | −4.5 |
11-20 | 11.9 | 7.8 | −13.9 |
>20 | 5.8 | 4.8 | −4.4 |
Combined Model score (mean (SD))** | 27.0 (20.2) | 26.1 (20.1) | −4.3 |
Low risk | 14.6 | 15.9 | 3.5 |
Moderate risk | 30.0 | 32.1 | 4.5 |
High risk | 44.3 | 41.6 | −5.6 |
Very high risk | 11.1 | 10.5 | −1.9 |
Analyses of differences in contact rates during the trial period
Before | After | Difference-in-difference | ||||
---|---|---|---|---|---|---|
Control | Intervention | Control | Intervention | Estimate | P | |
GP contacts | 8.98 (7.61) | 8.84 (6.76) | 8.85 (8.16) | 8.99 (7.00) | 0.29 | 0.465 |
Practice nurse contacts | 6.07 (8.07) | 5.26 (7.76) | 6.28 (8.98) | 5.92 (9.83) | 0.45 | 0.245 |
Clinical readings* | 2.76 (2.59) | 2.73 (2.47) | 2.71 (2.53) | 2.80 (2.76) | 0.11 | 0.414 |
Endpoint (interpretation) | Model | Estimate (95% CI) | P |
---|---|---|---|
General practitioner contacts | Unadjusted | 1.05 (0.90 to 1.23) | 0.520 |
Adjusted | 1.04 (0.95 to 1.14) | 0.404 | |
Combined model | 1.04 (0.90 to 1.21) | 0.560 | |
Practice nurse contacts | Unadjusted | 1.14 (0.81 to 1.61) | 0.438 |
Adjusted | 1.04 (0.82 to 1.30) | 0.756 | |
Combined model | 1.13 (0.81 to 1.58) | 0.468 | |
Clinical readings* | Unadjusted | 1.01 (0.85 to 1.20) | 0.881 |
Adjusted | 1.00 (0.90 to 1.12) | 0.931 |