install.packages("DrugUtilisation")An R package to conduct Drug Utilisation Studies in the OMOP CDM
Drug Utilisation Studies (DUS) were defined by the World Health Organization as studying the marketing, distribution, prescription, and use of medicinal products in a society, with special emphasis on the resulting medical and socioeconomic consequences (WHO, 2003).
This package aims to standardise and provide the tools to conduct Drug Utilisation studies as of the Darwin-EU Catalogue of Standard Analytics.

For this example we are going to use the GiBleed synthetic test database:
library(omock)
library(duckdb)
library(CDMConnector)
library(dplyr)
library(CodelistGenerator)
library(DrugUtilisation)
library(CohortConstructor)
library(PatientProfiles)
library(ggplot2)
library(clock)
library(omopgenerics)
library(CohortSurvival)
cdm <- mockCdmFromDataset(datasetName = "GiBleed", source = "duckdb")
cdm$drug_exposure <- cdm$drug_exposure |>
mutate(quantity = sql("floor(random() * 6) + 1")) |>
mutate(quantity = case_when(
quantity == 1 ~ 0,
quantity == 2 ~ 1,
quantity == 3 ~ 5,
quantity == 4 ~ 10,
quantity == 5 ~ 30,
quantity == 6 ~ 100
)) |>
compute(name = "drug_exposure")For this example we are going to use all records of acteaminophen:
The results is the cdm object with the new cohort instantiated.
── # OMOP CDM reference (duckdb) of GiBleed ────────────────────────────────────────────────────────────────────────────
• omop tables: care_site, cdm_source, concept, concept_ancestor, concept_class, concept_relationship, concept_synonym,
condition_era, condition_occurrence, cost, death, device_exposure, domain, dose_era, drug_era, drug_exposure,
drug_strength, fact_relationship, location, measurement, metadata, note, note_nlp, observation, observation_period,
payer_plan_period, person, procedure_occurrence, provider, relationship, source_to_concept_map, specimen, visit_detail,
visit_occurrence, vocabulary
• cohort tables: dus_cohort
• achilles tables: -
• other tables: -
The cohort objects have some attributes:
[1] "cohort_table" "cdm_table" "GeneratedCohortSet" "tbl_duckdb_connection"
[5] "tbl_dbi" "tbl_sql" "tbl_lazy" "tbl"
Settings:
# A tibble: 1 × 4
cohort_definition_id cohort_name cdm_version vocabulary_version
<int> <chr> <chr> <chr>
1 1 acetaminophen 5.3 v5.0 18-JAN-19
Cohort attrition:
# A tibble: 4 × 7
cohort_definition_id number_records number_subjects reason_id reason excluded_records excluded_subjects
<int> <int> <int> <int> <chr> <int> <int>
1 1 14205 2679 1 Initial qualifying e… 0 0
2 1 14205 2679 2 Record in observation 0 0
3 1 14205 2679 3 Not missing record d… 0 0
4 1 13908 2679 4 Merge overlapping re… 297 0
gapEra parameter can be used to concatenate different records.
Number of days between two continuous exposures to be considered in the same era. Records that have fewer days between them than this gap will be concatenated into the same cohort record.
# A tibble: 5 × 7
cohort_definition_id number_records number_subjects reason_id reason excluded_records excluded_subjects
<int> <int> <int> <int> <chr> <int> <int>
1 1 14205 2679 1 Initial qualifying e… 0 0
2 1 14205 2679 2 Record in observation 0 0
3 1 14205 2679 3 Not missing record d… 0 0
4 1 13908 2679 4 Merge overlapping re… 297 0
5 1 13860 2679 5 Collapse cohort with… 48 0
Four functions to add inclusion criteria to our cohort:
requirePriorDrugWashout() (requireConceptIntersect)requireIsFirstDrugEntry() (requireIsFirstEntry)requireObservationBeforeDrug() (requirePriorObservation)requireDrugInDateRange() (requireInDateRange)Not all inclusion criteria are commutable operations (A + B != B + A):
Not commutable:
prior washout + prior observation != prior observation + prior washoutprior washout + first != first + prior washoutprior washout + date range != date range + prior washoutfirst + prior observation != prior observation + firstfirst + date range != date range + firstCommutable:
date range + prior observation == prior observation + date rangeHaving all this into account the recommended order to apply criteria would be:
Require a prior drug washout or require first drug entry (particular case).
Require a prior observation before the drug episode.
Require the drugs to be in a certain date range.
https://darwin-eu-dev.github.io/DrugUtilisation/articles/create_cohorts.html
result <- cdm$dus_cohort |>
summariseDrugUtilisation(
ingredientConceptId = 1125315L,
indexDate = "cohort_start_date",
censorDate = "cohort_end_date",
restrictIncident = TRUE,
gapEra = 30,
numberExposures = TRUE,
numberEras = TRUE,
daysExposed = TRUE,
daysPrescribed = TRUE,
timeToExposure = FALSE,
initialQuantity = TRUE,
cumulativeQuantity = TRUE,
initialDailyDose = TRUE,
cumulativeDose = TRUE,
estimates = c("q25", "median", "q75")
)| Concept set | Ingredient | Variable name | Estimate name |
CDM name
|
|---|---|---|---|---|
| GiBleed | ||||
| acetaminophen | ||||
| overall | overall | number records | N | 13,860 |
| number subjects | N | 2,679 | ||
| ingredient_1125315_descendants | overall | number exposures | Median (Q25 - Q75) | 1 (1 - 1) |
| cumulative quantity | Median (Q25 - Q75) | 10.00 (1.00 - 30.00) | ||
| initial quantity | Median (Q25 - Q75) | 10.00 (1.00 - 30.00) | ||
| initial exposure duration | Median (Q25 - Q75) | 15 (8 - 15) | ||
| number eras | Median (Q25 - Q75) | 1 (1 - 1) | ||
| days exposed | Median (Q25 - Q75) | 15 (8 - 15) | ||
| days prescribed | Median (Q25 - Q75) | 15 (8 - 15) | ||
| Acetaminophen | cumulative dose milligram | Median (Q25 - Q75) | 1,625.00 (217.00 - 9,750.00) | |
| initial daily dose milligram | Median (Q25 - Q75) | 108.33 (13.56 - 443.18) | ||
summariseIndication():
To summarise mutually exclusive indications.
Define a window respect to the ‘cohort_start_date’.
Indications must be instantiated beforehand as cohorts.
Unknown indication (check a table to see if there is a record).
Let’s instantiate the cohorts of interest:
Rows: 40
Columns: 13
$ result_id <int> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, …
$ cdm_name <chr> "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBl…
$ group_name <chr> "cohort_name", "cohort_name", "cohort_name", "cohort_name", "cohort_name", "cohort_name", "co…
$ group_level <chr> "acetaminophen", "acetaminophen", "acetaminophen", "acetaminophen", "acetaminophen", "acetami…
$ strata_name <chr> "overall", "overall", "overall", "overall", "overall", "overall", "overall", "overall", "over…
$ strata_level <chr> "overall", "overall", "overall", "overall", "overall", "overall", "overall", "overall", "over…
$ variable_name <chr> "Indication on index date", "Indication on index date", "Indication on index date", "Indicati…
$ variable_level <chr> "arteriosclerosis", "arteriosclerosis", "myocardial_infarction", "myocardial_infarction", "pa…
$ estimate_name <chr> "count", "percentage", "count", "percentage", "count", "percentage", "count", "percentage", "…
$ estimate_type <chr> "integer", "percentage", "integer", "percentage", "integer", "percentage", "integer", "percen…
$ estimate_value <chr> "0", "0", "64", "0.461760461760462", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "13633…
$ additional_name <chr> "window_name", "window_name", "window_name", "window_name", "window_name", "window_name", "wi…
$ additional_level <chr> "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 …
CDM name
|
||
|---|---|---|
GiBleed
|
||
| Indication | Estimate name |
Cohort name
|
| acetaminophen | ||
| Indication on index date | ||
| arteriosclerosis | N (%) | 0 (0.00 %) |
| myocardial_infarction | N (%) | 64 (0.46 %) |
| pain | N (%) | 0 (0.00 %) |
| arteriosclerosis and myocardial_infarction | N (%) | 0 (0.00 %) |
| arteriosclerosis and pain | N (%) | 0 (0.00 %) |
| myocardial_infarction and pain | N (%) | 0 (0.00 %) |
| arteriosclerosis and myocardial_infarction and pain | N (%) | 0 (0.00 %) |
| unknown | N (%) | 13,633 (98.36 %) |
| none | N (%) | 163 (1.18 %) |
| not in observation | N (%) | 0 (0.00 %) |
| Indication from 30 days before to 7 days after the index date | ||
| arteriosclerosis | N (%) | 5 (0.04 %) |
| myocardial_infarction | N (%) | 64 (0.46 %) |
| pain | N (%) | 0 (0.00 %) |
| arteriosclerosis and myocardial_infarction | N (%) | 0 (0.00 %) |
| arteriosclerosis and pain | N (%) | 0 (0.00 %) |
| myocardial_infarction and pain | N (%) | 0 (0.00 %) |
| arteriosclerosis and myocardial_infarction and pain | N (%) | 0 (0.00 %) |
| unknown | N (%) | 13,784 (99.45 %) |
| none | N (%) | 7 (0.05 %) |
| not in observation | N (%) | 0 (0.00 %) |
Output of ploting functions are ggplot2 objects.
Currently considering to add support for plotly.
Let’s say we conducted the analysis stratified by sex:
Rows: 120
Columns: 13
$ result_id <int> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, …
$ cdm_name <chr> "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBl…
$ group_name <chr> "cohort_name", "cohort_name", "cohort_name", "cohort_name", "cohort_name", "cohort_name", "co…
$ group_level <chr> "acetaminophen", "acetaminophen", "acetaminophen", "acetaminophen", "acetaminophen", "acetami…
$ strata_name <chr> "overall", "overall", "overall", "overall", "overall", "overall", "overall", "overall", "over…
$ strata_level <chr> "overall", "overall", "overall", "overall", "overall", "overall", "overall", "overall", "over…
$ variable_name <chr> "Indication on index date", "Indication on index date", "Indication on index date", "Indicati…
$ variable_level <chr> "arteriosclerosis", "arteriosclerosis", "myocardial_infarction", "myocardial_infarction", "pa…
$ estimate_name <chr> "count", "percentage", "count", "percentage", "count", "percentage", "count", "percentage", "…
$ estimate_type <chr> "integer", "percentage", "integer", "percentage", "integer", "percentage", "integer", "percen…
$ estimate_value <chr> "0", "0", "64", "0.461760461760462", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "13633…
$ additional_name <chr> "window_name", "window_name", "window_name", "window_name", "window_name", "window_name", "wi…
$ additional_level <chr> "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 to 0", "0 …
You can do the same plot by year:
result <- cdm$dus_cohort |>
requireDrugInDateRange(
name = "new_cohort",
dateRange = as.Date(c("1990-01-01", "1999-12-31"))
) |>
mutate(year = get_year(cohort_start_date)) |>
summariseIndication(
strata = "year",
indicationCohortName = "indications",
indicationWindow = c(-Inf, 0),
unknownIndicationTable = "condition_occurrence"
)
result |>
filterStrata(year != "overall") |>
plotIndication(x = "year")To analyse treatment persistence and adherence there are two standard pipelines:
Survival analysis (implemented in the CohortSurvival package)
Proportion of patients covered
Proportion of treated individuals between index date and followUpDays. Percentages will be reported daily.
| Time | Estimate name |
Cohort name
|
|---|---|---|
| acetaminophen | ||
| GiBleed | ||
| 0 | PPC (95%CI) | 100.00% [99.86% - 100.00%] |
| 1 | PPC (95%CI) | 98.69% [98.19% - 99.06%] |
| 2 | PPC (95%CI) | 98.69% [98.19% - 99.06%] |
| 3 | PPC (95%CI) | 98.69% [98.19% - 99.06%] |
| 4 | PPC (95%CI) | 98.69% [98.19% - 99.06%] |
| 5 | PPC (95%CI) | 98.69% [98.19% - 99.06%] |
| 6 | PPC (95%CI) | 98.69% [98.19% - 99.06%] |
| 7 | PPC (95%CI) | 98.66% [98.15% - 99.03%] |
| 8 | PPC (95%CI) | 74.73% [73.05% - 76.34%] |
| 9 | PPC (95%CI) | 74.73% [73.05% - 76.34%] |
| 10 | PPC (95%CI) | 74.73% [73.05% - 76.34%] |
| 11 | PPC (95%CI) | 74.73% [73.05% - 76.34%] |
| 12 | PPC (95%CI) | 74.73% [73.05% - 76.34%] |
| 13 | PPC (95%CI) | 74.73% [73.05% - 76.34%] |
| 14 | PPC (95%CI) | 74.62% [72.93% - 76.23%] |
| 15 | PPC (95%CI) | 19.48% [18.03% - 21.03%] |
| 16 | PPC (95%CI) | 19.37% [17.92% - 20.91%] |
| 17 | PPC (95%CI) | 19.26% [17.81% - 20.80%] |
| 18 | PPC (95%CI) | 19.26% [17.81% - 20.80%] |
| 19 | PPC (95%CI) | 19.22% [17.78% - 20.76%] |
| 20 | PPC (95%CI) | 19.22% [17.78% - 20.76%] |
| 21 | PPC (95%CI) | 19.19% [17.74% - 20.72%] |
| 22 | PPC (95%CI) | 14.37% [13.09% - 15.75%] |
| 23 | PPC (95%CI) | 14.33% [13.06% - 15.71%] |
| 24 | PPC (95%CI) | 14.33% [13.06% - 15.71%] |
| 25 | PPC (95%CI) | 14.30% [13.02% - 15.67%] |
| 26 | PPC (95%CI) | 14.30% [13.02% - 15.67%] |
| 27 | PPC (95%CI) | 14.30% [13.02% - 15.67%] |
| 28 | PPC (95%CI) | 14.30% [13.02% - 15.67%] |
| 29 | PPC (95%CI) | 11.35% [10.20% - 12.60%] |
| 30 | PPC (95%CI) | 11.27% [10.13% - 12.53%] |
| 31 | PPC (95%CI) | 8.40% [7.41% - 9.51%] |
| 32 | PPC (95%CI) | 8.36% [7.37% - 9.47%] |
| 33 | PPC (95%CI) | 8.36% [7.37% - 9.47%] |
| 34 | PPC (95%CI) | 8.36% [7.37% - 9.47%] |
| 35 | PPC (95%CI) | 8.32% [7.34% - 9.43%] |
| 36 | PPC (95%CI) | 5.97% [5.14% - 6.93%] |
| 37 | PPC (95%CI) | 5.97% [5.14% - 6.93%] |
| 38 | PPC (95%CI) | 5.71% [4.89% - 6.65%] |
| 39 | PPC (95%CI) | 5.64% [4.82% - 6.57%] |
| 40 | PPC (95%CI) | 5.56% [4.76% - 6.49%] |
| 41 | PPC (95%CI) | 5.56% [4.76% - 6.49%] |
| 42 | PPC (95%CI) | 5.56% [4.76% - 6.49%] |
| 43 | PPC (95%CI) | 5.56% [4.76% - 6.49%] |
| 44 | PPC (95%CI) | 5.52% [4.72% - 6.45%] |
| 45 | PPC (95%CI) | 5.45% [4.65% - 6.37%] |
| 46 | PPC (95%CI) | 5.45% [4.65% - 6.37%] |
| 47 | PPC (95%CI) | 5.45% [4.65% - 6.37%] |
| 48 | PPC (95%CI) | 5.56% [4.76% - 6.49%] |
| 49 | PPC (95%CI) | 5.56% [4.76% - 6.49%] |
| 50 | PPC (95%CI) | 5.56% [4.76% - 6.49%] |
| 51 | PPC (95%CI) | 5.52% [4.72% - 6.45%] |
| 52 | PPC (95%CI) | 5.52% [4.72% - 6.45%] |
| 53 | PPC (95%CI) | 5.52% [4.72% - 6.45%] |
| 54 | PPC (95%CI) | 5.52% [4.72% - 6.45%] |
| 55 | PPC (95%CI) | 5.52% [4.72% - 6.45%] |
| 56 | PPC (95%CI) | 5.49% [4.69% - 6.41%] |
| 57 | PPC (95%CI) | 5.49% [4.69% - 6.41%] |
| 58 | PPC (95%CI) | 5.75% [4.93% - 6.69%] |
| 59 | PPC (95%CI) | 5.75% [4.93% - 6.69%] |
| 60 | PPC (95%CI) | 5.82% [5.00% - 6.77%] |
| 61 | PPC (95%CI) | 3.28% [2.67% - 4.03%] |
| 62 | PPC (95%CI) | 3.40% [2.77% - 4.15%] |
| 63 | PPC (95%CI) | 3.32% [2.71% - 4.07%] |
| 64 | PPC (95%CI) | 3.32% [2.71% - 4.07%] |
| 65 | PPC (95%CI) | 3.32% [2.71% - 4.07%] |
| 66 | PPC (95%CI) | 3.40% [2.77% - 4.15%] |
| 67 | PPC (95%CI) | 3.40% [2.77% - 4.15%] |
| 68 | PPC (95%CI) | 3.17% [2.57% - 3.91%] |
| 69 | PPC (95%CI) | 3.17% [2.57% - 3.91%] |
| 70 | PPC (95%CI) | 3.10% [2.51% - 3.82%] |
| 71 | PPC (95%CI) | 3.10% [2.51% - 3.82%] |
| 72 | PPC (95%CI) | 3.06% [2.47% - 3.78%] |
| 73 | PPC (95%CI) | 2.87% [2.31% - 3.58%] |
| 74 | PPC (95%CI) | 2.84% [2.27% - 3.54%] |
| 75 | PPC (95%CI) | 2.80% [2.24% - 3.49%] |
| 76 | PPC (95%CI) | 2.76% [2.21% - 3.45%] |
| 77 | PPC (95%CI) | 2.76% [2.21% - 3.45%] |
| 78 | PPC (95%CI) | 2.84% [2.27% - 3.54%] |
| 79 | PPC (95%CI) | 2.87% [2.31% - 3.58%] |
| 80 | PPC (95%CI) | 2.87% [2.31% - 3.58%] |
| 81 | PPC (95%CI) | 2.80% [2.24% - 3.49%] |
| 82 | PPC (95%CI) | 2.80% [2.24% - 3.49%] |
| 83 | PPC (95%CI) | 2.80% [2.24% - 3.49%] |
| 84 | PPC (95%CI) | 2.80% [2.24% - 3.49%] |
| 85 | PPC (95%CI) | 2.80% [2.24% - 3.49%] |
| 86 | PPC (95%CI) | 2.80% [2.24% - 3.49%] |
| 87 | PPC (95%CI) | 2.80% [2.24% - 3.49%] |
| 88 | PPC (95%CI) | 2.84% [2.27% - 3.54%] |
| 89 | PPC (95%CI) | 2.91% [2.34% - 3.62%] |
| 90 | PPC (95%CI) | 2.91% [2.34% - 3.62%] |
gapEra parameter can have a big impact in survival analysis, whereas it does not have such big impact on proportion of patients covered.
We have the ability to study drug restart or drug switching after a discontinuation:
Switching cohorts must be defined in advance.
We have to define the windows of interest.
Index date will be the date of discontinuation.
Reported percentages in each window will be:
Restart: individuals that restarted and not switched.
Switch: individuals that switched and not restarted.
Restart and switch: individuals that restarted and switched.
Untreated: individuals that did not restart or switch.
Let’s define the cohorts of interest for switching:
We have to be careful with the inclusion criteria of the input cohort, as restart is derived from it.
Rows: 32
Columns: 13
$ result_id <int> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
$ cdm_name <chr> "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBleed", "GiBl…
$ group_name <chr> "cohort_name", "cohort_name", "cohort_name", "cohort_name", "cohort_name", "cohort_name", "co…
$ group_level <chr> "acetaminophen", "acetaminophen", "acetaminophen", "acetaminophen", "acetaminophen", "acetami…
$ strata_name <chr> "overall", "overall", "overall", "overall", "overall", "overall", "overall", "overall", "over…
$ strata_level <chr> "overall", "overall", "overall", "overall", "overall", "overall", "overall", "overall", "over…
$ variable_name <chr> "Drug restart in 90 days", "Drug restart in 90 days", "Drug restart in 90 days", "Drug restar…
$ variable_level <chr> "restart", "restart", "switch", "switch", "restart and switch", "restart and switch", "untrea…
$ estimate_name <chr> "count", "percentage", "count", "percentage", "count", "percentage", "count", "percentage", "…
$ estimate_type <chr> "integer", "percentage", "integer", "percentage", "integer", "percentage", "integer", "percen…
$ estimate_value <chr> "43", "1.60507652108996", "0", "0", "0", "0", "2636", "98.39492347891", "97", "3.620754012691…
$ additional_name <chr> "follow_up_days", "follow_up_days", "follow_up_days", "follow_up_days", "follow_up_days", "fo…
$ additional_level <chr> "90 days", "90 days", "90 days", "90 days", "90 days", "90 days", "90 days", "90 days", "180 …
CDM name
|
||
|---|---|---|
GiBleed
|
||
| Treatment | Estimate name |
Cohort name
|
| acetaminophen | ||
| Drug restart in 90 days | ||
| restart | N (%) | 43 (1.61 %) |
| switch | N (%) | 0 (0.00 %) |
| restart and switch | N (%) | 0 (0.00 %) |
| untreated | N (%) | 2,636 (98.39 %) |
| Drug restart in 180 days | ||
| restart | N (%) | 97 (3.62 %) |
| switch | N (%) | 0 (0.00 %) |
| restart and switch | N (%) | 0 (0.00 %) |
| untreated | N (%) | 2,582 (96.38 %) |
| Drug restart in 270 days | ||
| restart | N (%) | 175 (6.53 %) |
| switch | N (%) | 0 (0.00 %) |
| restart and switch | N (%) | 0 (0.00 %) |
| untreated | N (%) | 2,504 (93.47 %) |
| Drug restart in 360 days | ||
| restart | N (%) | 244 (9.11 %) |
| switch | N (%) | 1 (0.04 %) |
| restart and switch | N (%) | 0 (0.00 %) |
| untreated | N (%) | 2,434 (90.85 %) |
summariseTreatment() is a general function to analyse presence of treatments (cohorts) after an index date. This can be used with many different purposes:
Summarise treatments after a certain condition
Analyse comedications
Analyse treatments after discontinuation
…
codelist <- getDrugIngredientCodes(
cdm = cdm,
name = c("clopidogrel", "simvastatin", "warfarin", "nitroglycerin"),
nameStyle = "{concept_name}"
)
cdm$treatments <- conceptCohort(
cdm = cdm,
name = "treatments",
conceptSet = codelist
)
cdm$osteoarthritis <- conceptCohort(
cdm = cdm,
conceptSet = list(osteoarthritis = 80180L),
name = "osteoarthritis"
)
CDM name
|
||
|---|---|---|
GiBleed
|
||
| Treatment | Estimate name |
Cohort name
|
| osteoarthritis | ||
| Medication from 1 day after to 90 days after the index date | ||
| clopidogrel | N (%) | 9 (0.34 %) |
| nitroglycerin | N (%) | 20 (0.76 %) |
| simvastatin | N (%) | 1 (0.04 %) |
| warfarin | N (%) | 0 (0.00 %) |
| untreated | N (%) | 2,608 (99.16 %) |
| not in observation | N (%) | 0 (0.00 %) |
| Medication from 91 days after to 180 days after the index date | ||
| clopidogrel | N (%) | 10 (0.38 %) |
| nitroglycerin | N (%) | 20 (0.76 %) |
| simvastatin | N (%) | 0 (0.00 %) |
| warfarin | N (%) | 0 (0.00 %) |
| untreated | N (%) | 2,583 (98.21 %) |
| not in observation | N (%) | 25 (0.95 %) |
| Medication from 181 days after to 270 days after the index date | ||
| clopidogrel | N (%) | 9 (0.34 %) |
| nitroglycerin | N (%) | 20 (0.76 %) |
| simvastatin | N (%) | 1 (0.04 %) |
| warfarin | N (%) | 0 (0.00 %) |
| untreated | N (%) | 2,569 (97.68 %) |
| not in observation | N (%) | 40 (1.52 %) |
| Medication from 271 days after to 360 days after the index date | ||
| clopidogrel | N (%) | 11 (0.42 %) |
| nitroglycerin | N (%) | 21 (0.80 %) |
| simvastatin | N (%) | 1 (0.04 %) |
| warfarin | N (%) | 0 (0.00 %) |
| untreated | N (%) | 2,547 (96.84 %) |
| not in observation | N (%) | 60 (2.28 %) |