Value of clinical trial narrative data to estimate the costs of adverse event management: a feasibility study

Figures & data

Figure 1. Flow diagram for number of grade 3–4 adverse events costed, by adverse event. HCRU: health care resource use.

Table 1. Percentages of AEs eligible for costing with information recorded in patient narratives pertaining to key HCRU: nausea.

	n (%)
Number of AEs eligible for costing	33
Number of AEs in which narratives indicated that patients received medication (a)	25 (75.8%)
Number of AEs for which narratives indicated that patients were hospitalized (b)	26 (78.8%)
Number of AEs for which narratives indicated that patients received medication (a) and were hospitalized (b)	18 (54.5%)

The 33 nausea AEs that were eligible for costing occurred in 31 patients. Key HCRU was defined as medications and inpatient hospitalizations. 100% of AEs eligible for costing recorded use of medication or hospitalization. No other resources were recorded other than seven ED visits, all of which coincided with a hospital admission, and one instance of a computed tomography scan.

Abbreviations. AE, adverse event; ED, emergency department; HCRU, health care resource use.

Table 2. Percentages of AEs eligible for costing with information recorded in patient narratives pertaining to key HCRU: thrombocytopenia.

	n (%)
Number of AEs eligible for costing	68
Number of AEs in which narratives indicated that platelet count was assessed	66 (97.1%)
Number of AEs in which narratives indicated that patients received a platelet transfusion (a)	16 (23.5%)
Number of AEs for which narratives indicated that patients were hospitalized (b)	13 (19.1%)
Number of AEs for which narratives indicated that patients received a platelet transfusion (a) and were hospitalized (b)	8 (11.8%)

The 68 thrombocytopenia AEs that were eligible for costing occurred in 53 patients. Key HCRU was defined as platelet count assessments, platelet transfusions, and inpatient hospitalizations. 100% of AEs eligible for costing recorded use of a key HCRU. No other resources were recorded other than one use of a nasal tampon, and three instances of medication use (eltrombopag, methylprednisolone, and dexamethasone).

Abbreviations. AE, adverse event; HCRU, health care resource use.

Table 3. Extent of known missing data for medication use: nausea.

	n (%)
Number of unique instances of medication use recorded in narratives	77
Number of instances for which medication formulation was not recorded	63 (81.8%)
Number of instances for which prescription duration was not recorded	33 (42.9%)
Number of instances for which formulation or duration was not recorded	66 (85.7%)

Table 4. Extent of known missing data for platelet transfusions: thrombocytopenia.

	n (%)
Number of unique instances of platelet transfusion recorded in narratives	27
Number of instances for which the number of units transfused was provided (a)	7 (25.9%)
Number of instances for which the type of platelets was specified (b)	8 (29.6%)
Number of instances for which number of units transfused (a) and type of platelets (b) were provided	1 (3.7%)

In all instances for which the medication end date was provided, the start date also was provided. Types of platelets were indicated as single donor (6), thrombocyte concentrate (1) and fresh, frozen plasma (1).

Table 5. Extent of missing data for duration of hospitalization.

	Nausea n (%)	Thrombocytopenia n (%)
Number of unique instances of inpatient hospitalizations recorded in narratives	27	13
Number of hospitalizations where both admission date and discharge date were provided	22 (81.5%)	8 (61.5%)
Number of hospitalizations where only the admission date was provided	4 (14.8%)	3 (23.1%)
Number of hospitalizations where only the discharge date was provided	1 (3.7%)	1 (7.7%)
Number of hospitalizations where neither the admission date nor the discharge date was provided	0 (0.0%)	1 (7.7%)

Of the 22 hospitalizations for nausea where both admission and discharge dates were provided, four patients died prior to discharge or resolution of the adverse event, in which case date of discharge was set to date of death.

Table 6. Costs to treat nausea (all events recorded as Grade 3), per adverse event (2017 USD), by resource use component.

Resource use cost component (no. of AEs = 33)	Mean	SD	Median	Minimum	Maximum
Medication cost per event (including 8 events with no medication cost)	$721.13	$2,214.81	$151.73	$0	$12,731.22
Medication administration cost per event (including 21 with no medication administration cost)	$354.14	$1,064.03	$0	$0	$6,08;8.26
ED visit cost per event (including 26 with no ED visit cost)	$281.43	$550.79	$0	$0	$1,326.74
CT scan cost per event (including 32 with no CT scan cost)	$7.66	$44.00	$0	$0	$252.74
Total cost per event excluding hospitalization costs	$1,364.36	$2,615.50	$731.87	$0	$14,310.70
Hospitalization cost per event (including 7 with no hospitalization cost)	$12,319.75	$11,948.99	$8,691.13	$0	$53,112.47
Total cost per event including hospitalization costs (including 6 with no hospitalization cost)	$13,684.11	$12,745.16	$9,656.81	$28.60	$53,684.08

Results in this table are based on data from 33 events experienced by 31 patients. All results are based on the data set that includes imputed data.

Abbreviations. AE, adverse event; ED, emergency department; CT, computed tomography; SD, standard deviation; USD, US dollars.

Table 7. Costs to treat grade 3–4 thrombocytopenia per event (2017 USD), by resource use component.

Resource Use Component	Grade 3 (no. of events = 42)		Grade 4 (no. of events = 26)		All Grade 3-4 Events (no. of events = 68)
	Mean	SD	Mean	SD	Mean	SD	Median	Min	Max
Medication cost per event (including 65 with no medication cost)	$2.91	$18.84	$3.27	$15.55	$3.05	$17.53	$0	$0	$122.08
Platelet transfusion cost per event (including 52 with no platelet transfusion cost)	$49.30	$223.14	$1,393.62	$2,027.47	$563.30	$1,413.31	$0	$0	$8,282.08
Bleeding procedure cost per event (including 67 with no bleeding procedure cost)	$0	$0	$6.50	$33.13	$2.48	$20.49	$0	$0	$168.95
Laboratory assessment cost per event (including 2 with no laboratory assessment cost)	$26.20	$23.03	$25.92	$19.97	$26.09	$21.75	$17.06	$0	$102.36
ED visit cost per event (including 67 with no ED visit cost)	$0	$0	$51.03	$260.19	$19.51	$160.89	$0	$0	$1,326.74
Total cost per event excluding hospitalization costs	$78.40	$227.90	$1,480.33	$2,071.41	$614.44	$1,450.47	$25.59	$0	$8,324.73
Hospitalization cost per event (including 55 with no hospitalization cost)	$3,113.82	$9,982.51	$4,210.31	$7,442.03	$3,533.06	9,051.73	$0	$0	$53,280.88
Total cost per event including hospitalization costs (including 55 with no hospitalization cost)	$3,192.22	$10,003.50	$5,690.64	$8,636.67	$4,147.50	$9,516.61	$34.12	$8.53	$53,280.88

Results in this table are based on data from 68 events experienced by 51 patients. All results are based on the data set that includes imputed data.

Abbreviations. ED, emergency department; SD, standard deviation; USD, US dollars.

Table 8. Impact of imputing missing data for hospitalization.

	Nausea	Thrombocytopenia
Average cost per hospitalization when including imputed values for missing data	$15,057.48 (n = 27)	$18,480.64 (n = 13)
Average cost per hospitalization when including only non-missing data	$16,679.95 (n = 22)	$17,861.20 (n = 8)