Follow-up yield and characteristics of responders vs. non-responders
Of the 472 patients in the baseline cohort, 329 could be reached by follow-up efforts. Interviews were conducted with 266 participants, while 63 returned a printed questionnaire. The dropout rate was 30.3%, with Table
1 showing reasons for participants being lost to follow-up. We know of 15 patients (3.18%) who died in the period between index visit and intended follow-up.
Table 1
Yield of follow-up efforts and reasons for dropout
Baseline survey | 472 | – |
Follow-up survey | 329 | – |
Lost to follow-up | 143 | 100.0 |
Died | 15 | 10.5 |
Could not be reached: moved with no forwarding address obtainable (incl. to other countries), invalid phone/e-mail, or not answering at multiple contact attempts | 73 | 51.0 |
Patient reached and consented to follow-up, but did not return questionnaire | 19 | 13.3 |
Patient reached, but refused to participate | 36 | 25.2 |
Most frequent reasons stated: |
Language barrier | 12 | 8.4 |
Time constraints | 6 | 4.2 |
Health status | 6 | 4.2 |
Median follow-up time (distance to baseline) was 95 days, with a range of 82 to 206 days. Most patients were followed up at three to four months after the index visit, with the 95th percentile of follow-up length at 133 days.
Table
2 summarizes basic demographic and medical characteristics of the total baseline cohort and the subgroup of patients with available follow-up.
Table 2
Data from baseline survey: characteristics of total cohort, patients with follow-up data available, follow-up non-participants (total), patients who died prior to intended follow-up, and follow-up non-participants excluding patients who died
Participants | n | 472 | 329 | 143 | 15 | 128 |
Demographics |
Age | n | 472 | 329 | 143 | 15 | 128 |
Mean (SD) | 53.6 (19.2) | 54.6 (18.3) | 51.3 (21.0) | 79.7 (7.1) | 48.0 (19.5) |
Median (Range) | 55.0 (18–96) | 56.0 (18–92) | 51.0 (18–96) | 81.0 (67–92) | 46.0 (18–96) |
Sex | n | 472 | 329 | 143 | 15 | 128 |
Male | % | 53.2 | 52.9 | 53.8 | 73.3 | 51.6 |
Female | % | 46.8 | 47.1 | 46.2 | 26.7 | 48.4 |
Migration and travel | n | 466 | 326 | 140 | 15 | 125 |
Migrant first generation | % | 21.9 | 17.2 | 32.9 | 6.7 | 36.0 |
Second generation | % | 6.9 | 6.1 | 8.6 | 0.0 | 9.6 |
Tourist | % | 4.3 | 1.2 | 11.4 | 0.0 | 12.8 |
Education (CASMIN) | n | 463 | 325 | 138 | 15 | 123 |
Low | % | 25.5 | 23.7 | 29.7 | 73.3 | 24.4 |
Intermediate | % | 43.6 | 46.8 | 36.2 | 20.0 | 38.2 |
High | % | 30.9 | 29.5 | 34.1 | 6.7 | 37.4 |
ED consultation |
Means of arrival | n | 462 | 319 | 143 | 15 | 128 |
Walk-in | % | 63.0 | 60.2 | 69.2 | 26.7 | 74.2 |
EMS | % | 30.7 | 31.7 | 28.7 | 73.3 | 23.4 |
Ambulance transport | % | 6.3 | 8.2 | 2.1 | 0.0 | 2.3 |
Initiation of visit | n | 465 | 325 | 140 | 15 | 125 |
Self-referred | % | 62.8 | 59.4 | 70.7 | 60.0 | 72.0 |
Health professional | % | 37.2 | 40.6 | 29.3 | 40.0 | 28.0 |
Triage category | n | 456 | 317 | 139 | 14 | 125 |
Lower urgency | % | 41.9 | 40.4 | 45.3 | 0.0 | 50.4 |
Higher urgency | % | 58.1 | 59.6 | 54.7 | 100.0 | 49.6 |
Time of presentation | n | 472 | 329 | 143 | 15 | 128 |
Out-of-hours visit | % | 17.2 | 16.7 | 18.2 | 33.3 | 16.4 |
During office hours | % | 82.8 | 83.3 | 81.8 | 66.7 | 83.6 |
ED symptoms |
Symptom novelty | n | 467 | 326 | 141 | 15 | 126 |
New symptoms | % | 36.4 | 37.7 | 33.3 | 0.0 | 37.3 |
Recurrent symptoms | % | 63.6 | 62.3 | 66.7 | 100.0 | 62.7 |
Symptom-associated distress | n | 442 | 312 | 130 | | |
Mean (SD) | 7.2 (1.8) | 7.3 (1.8) | 7.0 (1.9) | 7.4 (1.9) | 6.9 (1.9) |
Median (Range) | 7.5 (1.5–10) | 7.5 (2.0–10) | 7.0 (1.5–10) | 8.0 (3.5–9.5) | 7.0 (1.5–10) |
Chronic conditions and care |
Chronic pulmonary condition | n | 467 | 326 | 141 | 15 | 126 |
yes: % | 58.7 | 62.0 | 51.1 | 66.7 | 49.2 |
Multimorbidity | n | 465 | 325 | 140 | 15 | 125 |
yes: % | 53.5 | 58.8 | 41.4 | 73.3 | 37.6 |
Attached to GP | n | 464 | 323 | 141 | 15 | 126 |
yes: % | 86.6 | 90.7 | 77.3 | 100.0 | 74.6 |
Mental and general health |
PHQ-4 anxiety subscale | n | 467 | 326 | 141 | 15 | 126 |
Mean (SD) | 1.7 (1.9) | 1.6 (1.8) | 2.0 (2.0) | 1.8 (2.1) | 2.0 (2.0) |
Median (Range) | 1.0 (0–6) | 1.0 (0–6) | 1.0 (0–6) | 1.0 (0–6) | 1.0 (0–6) |
PHQ-4 depression subscale | n | 467 | 326 | 141 | 15 | 126 |
Mean (SD) | 2.2 (2.2) | 2.1 (2.1) | 2.4 (2.3) | 2.7 (2.3) | 2.3 (2.3) |
Median (Range) | 2.0 (0–6) | 2.0 (0–6) | 2.0 (0–6) | 3.0 (0–6) | 2.0 (0–6) |
General life satisfaction | n | 457 | 321 | 136 | 15 | 121 |
Mean (SD) | 6.9 (2.6) | 7.1 (2.5) | 6.7 (2.8) | 6.4 (3.1) | 6.7 (2.8) |
Median (Range) | 8.0 (0–10) | 8.0 (0–10) | 8.0 (0–10) | 8.0 (0–10) | 8.0 (0–10) |
General health | n | 466 | 325 | 141 | 15 | 126 |
Mean (SD) | 45.9 (25.0) | 45.8 (24.6) | 46.1 (25.9) | 33.2 (23.3) | 47.6 (25.8) |
Median (Range) | 50.0 (0–100) | 50.0 (0–100) | 50.0 (0–100) | 40.0 (0–80.0) | 50.0 (0–100) |
ED visit outcomes |
Diagnoses | n | 472 | 329 | 143 | 15 | 128 |
Pneumonia J12-J18 | % | 23.3 | 25.8 | 17.5 | 26.7 | 16.4 |
COPD and chronic bronchitis J40-J44 | % | 34.3 | 38.3 | 25.2 | 60.0 | 21.1 |
Asthma bronchiale J45-J46 | % | 9.7 | 8.8 | 11.9 | 0.0 | 13.3 |
Other respiratory tract infection J09-J11, J20-J22 | % | 8.5 | 8.5 | 8.4 | 0.0 | 9.4 |
Upper airway conditions J0x/J3x | % | 10.2 | 8.2 | 14.7 | 0.0 | 16.4 |
Respiratory symptom diagnosis only (R section code) | % | 14.4 | 14.0 | 15.4 | 13.3 | 15.6 |
Respiratory failure J96 | % | 19.5 | 20.7 | 16.8 | 46.7 | 13.3 |
Visit consequence | n | 472 | 329 | 143 | 15 | 128 |
Outpatients | % | 61.2 | 58.4 | 67.8 | 20.0 | 73.4 |
Hospital admission | % | 38.8 | 41.6 | 32.2 | 80.0 | 26.6 |
In the regression model of dropout determinants (434 cases, Nagelkerke’s R2 0.232, AUC 0.75, Hosmer-Lemshow test χ2 10.341, df = 8, p = 0.242), lower probabilities of response to follow-up could be seen for first-generation migrants (OR 0.340, 95% CI [0193;0.599], p < 0.001, reference category: no migration and travel characteristic present) and tourists (OR 0.033, 95% CI [0.009;0.128], p < 0.001, same reference category). Patients with high educational status (OR 2.042, 95% CI [1.035;4.032], p = 0.040, reference category: low educational status) and multimorbidity (OR 1.947, 95% CI [1.136;3.338], p = 0.015) showed higher likelihood to take part in the follow-up survey. This was also the case for patients reporting to have a GP (OR 2.296, 95% CI [1.187;4.441], p = 0.014), and patients with higher general life satisfaction ratings (OR 1.125, 95% CI [1.029;1.231], p = 0.010). Sex and age were included in the model as control variables.
A closer look at the 15 patients who reportedly died prior to intended follow-up shows that these were of high age (mean ~ 80 years) and predominantly male. Morbidity indicators (e.g. urgent triage categories, high share of chronic illness, respiratory failure diagnosed in nearly half, high rate of hospital admission) show that many were already very ill at the time of the index ED visit. It must be noted that death during the designated follow-up period was confirmed in these cases either by relatives reached by our contact efforts, or official municipal register information. Causes or manner of death were not investigated. For some patients (who e.g. moved to another country), no such data was available, so we cannot be absolutely certain that all patients listed in Table
1 as “could not be reached” were still alive three months after the ED index visit.
Post hoc assessment of the ED visit
Retrospective satisfaction ratings regarding the ED visit were high, with 79.7% (of 325 patients with data for this item) of affirmative answers on the 5-point Likert scale (ratings “very satisfied” or “satisfied”). Of the 66 patients who did not rate satisfaction in favorable categories, reasons for not being satisfied were inquired (multiple answers possible). Most frequent complaints were about waiting times (n = 42, 63.6%), symptoms not being taken seriously (n = 15, 22.7%), insufficient treatment for acute complaint (n = 16, 24.2%), unfriendly staff (n = 11, 16.7%) and lack of information regarding treatment (n = 8, 12.1%). Distribution of the dissatisfaction reasons stated did differ between the sexes. Symptoms not being taken seriously were criticized by 17.2% of men vs. 27.0% of women, insufficient treatment by 20.7% of men vs. 27.0% of women, unfriendly staff was reported by 20.7% of men vs. 13.5% of women, and lack of information received by 6.9% of men and 16.2% of women. As to waiting times there was no marked difference (62.1% in men, 64.9% in women).
In the index visit survey, patients had also been asked to rate their satisfaction with current ED treatment in a Likert-scaled item corresponding to the follow-up question. Of 281 follow-up patients with a respective baseline rating available, 87.9% had then selected “very satisfied” or “satisfied”, and rating in a thus combined category was concordant to the retrospective assessment at follow-up in 216 cases (76.9%). There were no significant longitudinal differences for satisfaction ratings if assessed by Wilcoxon signed-rank test (Likert scale interpreted as quasi-continuous, p = 0.432) or McNemar test (scale dichotomized in top two vs. other categories, p = 0.120). Data did not show a marked difference between consulters coming to the ED during office hours vs. off-hours (p = 0.423, Mann-Whitney-U-test, 325 cases).
Two hundred fifty-eight participants (81.4% of 317 patients with data for this item) stated that they had benefited from their ED visit. When inquired about reasons for assessing the ED visit as beneficial, aspects reported by 256 cases included the initiation of a necessary inpatient or outpatient treatment (50.4%), personal reassurance (46.1%), prevention of aggravation by timely intervention (47.3%), the detection of the complaints’ cause (40.6%) and feeling relieved (35.2%). Assessment of the ED visit as beneficial was moderately correlated with satisfaction (binarized to “very satisfied” / “satisfied” categories vs. other categories), with a phi coefficient of 0.52 (p < 0.001).
Univariable statistics indicated that patients with a pneumonia diagnosis did retrospectively assess the ED consultation significantly more frequently as beneficial (
p = 0.010), as well as patients with respiratory failure (
p = 0.001), while this was not the case for COPD, Asthma, RTI, or Upper Airway diagnoses. A rating of the visit as beneficial was also significantly more frequent in male patients (
p = 0.001), patients triaged as of high urgency (
p = 0.026) and self-referrers (
p = 0.025). Male sex, pneumonia, respiratory failure, and self-referral were confirmed as determinants of retrospectively assessing the ED visit as beneficial in a subsequent multivariable logistic model controlling for demographics (age, education, and migration). Triage was no longer significant in the multivariable analysis (Table
3). An additional graphical representation of the regression results is included in the Additional file
1 (Supplementary Fig. 1).
Table 3
Logistic regression model for rating ED visit as beneficial
Age | −0.011 | 0.010 | 0.249 | 0.989 | 0.970 | 1.008 |
Sex (male) | 0.917 | 0.335 | 0.006 | 2.501 | 1.298 | 4.819 |
Pneumonia | 1.079 | 0.458 | 0.018 | 2.941 | 1.199 | 7.214 |
Respiratory failure | 1.542 | 0.638 | 0.016 | 4.676 | 1.338 | 16.342 |
Self-referral | 0.854 | 0.344 | 0.013 | 2.350 | 1.197 | 4.613 |
Triage (higher urgency) | 0.305 | 0.335 | 0.363 | 1.357 | 0.703 | 2.619 |
Educationa | -intermediate | −0.160 | 0.450 | 0.721 | 0.852 | 0.353 | 2.056 |
-high | −0.252 | 0.481 | 0.600 | 0.777 | 0.303 | 1.996 |
Migrantb | −0.303 | 0.418 | 0.469 | 0.739 | 0.326 | 1.676 |
Further morbidity markers (diagnoses of asthma, RTI, upper respiratory conditions, presence of a chronic pulmonary condition), as well as variables on out-of-hours consultation, symptom-associated distress at baseline, and attachment to a GP, were also evaluated for the multivariable model, but did not show themselves relevant contributive factors.
We also explored possible associations of the manner of follow-up response (telephone vs. writing) regarding ratings of satisfaction and subjective benefit from the ED visit. As to satisfaction, there were differences: in the telephone group, 82.5% rated satisfaction in the two top categories, while only 67.7% did so in written questionnaires (p = 0.009, χ2 test). This did not apply to rating the ED visit as beneficial, where proportions corresponded (81.7 and 80.0%, p = 0.771). Data did neither suggest an influence of follow-up time on either outcome, which was explored by comparing patients followed up at up to 95 days (median follow-up time) and at more than 95 days.
When revisiting their ED consultation at follow-up, 66 participants (21.4% of 309 cases with available data) believed a GP could also have solved their problem. This corresponds to the overall assessment in the baseline survey, where 20.6% (of 277 cases followed up with baseline data available for this item) considered primary care a suitable alternative in their acute situation. There was no significant difference between time points (McNemar test p = 0.332, 260 cases).