There were 3,242 potential participants for this study. A total of 1,206 individuals (37.2%) were not contacted as their primary care provider did not wish to participate in the research study. A total of 212 participants did not meet the inclusion criteria, 651 declined to participate and 392 were unreachable after written communication and three telephone call attempts.
In total, 781 women (24.1%) were recruited to this study and randomised to have screening completed either in the primary care setting (n = 391) or the secondary care setting (n = 390). Baseline characteristics of the study participants are shown in Table 1.
There was evidence of a significant association between randomised location and proportion of screening uptake (Fig. 2). Of those randomised to have screening conducted in primary care, the proportion of screening uptake was 52.7% (n = 206) while for those randomised to have screening in secondary care, the proportion of screening uptake was 89.2% (n = 348) (Fig. 2). This difference of 36.5 percentage points was statistically significant (p < 0.001; 95% CI 30.7, 42.4).
Almost one-third of the women (n = 127; 32.5%) who were randomised to the primary care group had the test completed in the secondary care setting. Conversely only 2.3% (n = 9) of those randomised to the secondary care setting had the test completed in the primary care setting (Fig. 2). This difference of 30.2 percentage points in crossover between randomised site and actual screening site was statistically significant (p < 0.001; 95% CI 25.3, 35.0).
When assessing those who did not attend for screening at all, 14.8% (n = 58) of those randomised to primary care did not attend for screening compared with 8.5% (n = 33) of those randomised to secondary care (Fig. 2). This difference of 6.4 percentage points was statistically significant (p = 0.005; 95% CI 1.9, 10.8).
There was no evidence of a significant difference in the proportion of uptake of screening at the randomised location in the primary care group (n = 391) based on the presence of a practice nurse (p = 0.155) or the presence of multiple GPs in a practice (p = 0.921).
When examining the probability of uptake of screening, there was evidence (p < 0.001) of a significant relationship with age (Fig. 3). For those that were randomised to be screened in the primary care setting, the probability of uptake of screening or crossover increased with age; the probability of no uptake of screening was higher for younger participants but decreased with increasing age.
For those that were randomised to the secondary care setting, there was a low probability of crossover regardless of age. The probability of uptake of screening was high and increased further with increasing age. The probability of no uptake of screening decreased with increasing age.
The analysis of the interviews with the primary care providers yielded four central themes. The first three themes related to the primary care providers’ perceptions of the feasibility of GDM screening in the primary care setting. The last theme related to their perceptions of the appropriateness of GDM screening in primary care. Direct quotations relevant to each of the themes are provided in the electronic supplementary material (ESM) text.
Theme 1: workload barriers
Primary care providers described the workload associated with the provision of the OGTT as a barrier to the feasible provision of GDM screening in their practices. One of the key concerns relating to the workload revolved around the necessity for three blood draws in the OGTT and the time taken to complete these tasks.
Many primary care providers made reference to a practice nurse being better placed than a GP to administer the test and in most cases it was the practice nurse who administered the OGTTs in practices that employed a practice nurse. Practices not employing a nurse found participation in this trial particularly difficult.
Theme 2: logistical barriers
The logistical difficulties posed by the provision of GDM screening in primary care and the disruption to practice this caused were also reported as barriers to screening.
Primary care providers described GP practices as being centres that dealt with patients at short notice. These patients often presented as higher clinical priority than a GDM screening patient, which made it difficult to carry out the test protocol in an accurate and timely fashion.
Similarly, because of the nature of the test protocol and the necessity of blood draws at precise times, the requirement that a woman undergoing GDM screening may have to bypass other waiting patients was considered to be a difficulty.
When probed about being able to maintain the precise schedule of blood draw timings, primary care providers were unsure if this could be met within their service.
Rural practices may be located at a considerable distance from the laboratory where the bloods are analysed. In those practices, blood work was only completed in the practice on specified days each week and samples were collected by courier for delivery to the laboratory at a specific time. The coordination of GDM screening within this framework proved logistically difficult for many rural practices.
Theme 3: financial barriers
Another concern that primary care providers expressed regarding the feasibility of providing GDM screening in the primary care setting relates to the financial compensation which is received for the provision of the service.
Much of the concern about the financial remuneration appears to stem from a sense that more is being asked from primary care providers while their statutory payments are being cut simultaneously. Primary care providers appeared worried that GDM screening would be moved from secondary to primary care without any financial compensation being made. There also appears to be an overall sense of negativity and disillusionment among primary care providers presently, which may also be linked to their unwillingness to provide GDM screening
Theme 4: appropriateness of primary care screening
Despite the barriers to the provision of GDM screening, there was overwhelming positivity about the benefits of GDM screening occurring in a localised community-based setting rather than in regional secondary care settings. The primary care providers acknowledged that provision in the primary care setting was particularly beneficial from the point of view of the patient. This is particularly relevant to patients living at a considerable distance from the hospital screening location.
Primary care providers were also aware that provision of screening in GP practices would facilitate patient follow-up, which they perceived as beneficial.
As primary care providers are cognisant of the benefits to the patient and the opportunity that the primary care setting affords for increased levels of combined follow-up care, a number of primary care providers proposed an alternative screening option that would allow for the benefits of provision by primary care providers to be retained but without the difficulties previously reported. This proposal involved the screening service being provided in the community by a dedicated individual external to the workings of their practice, either in a community health centre or in the GP practice.