Hypertension derived variable

This function determines the hypertension status of a respondent based on their systolic and diastolic blood pressure measurements and medication usage.

Usage

derive_hypertension(
  bpmdpbps,
  bpmdpbpd,
  any_htn_med,
  ccc_32 = 2,
  cvd_status = 2,
  diab_status = 2,
  ckd_status = 2
)

Arguments

bpmdpbps

integer An integer representing the systolic blood pressure measurement of the respondent.

bpmdpbpd

integer An integer representing the diastolic blood pressure measurement of the respondent.

any_htn_med

integer An integer indicating whether the respondent is on medication for hypertension.

• 1: Yes

• 0: No

ccc_32

integer An optional integer indicating whether the respondent is actually on medication for hypertension.

• 1: Yes

• 2: No (default)

cvd_status

integer An optional integer indicating the presence of cardiovascular disease, affecting medication status.

• 1: Yes

• 2: No (default)

diab_status

integer An optional integer indicating the presence of diabetes, affecting blood pressure thresholds.

• 1: Yes

• 2: No (default)

ckd_status

integer An optional integer indicating the presence of chronic kidney disease, affecting blood pressure thresholds.

• 1: Yes

• 2: No (default)

Value

integer The hypertension status:

• 1: High blood pressure (BP >= 140/90 mmHg (or >= 130/80 mmHg if diabetes or CKD) or on hypertension medication)

• 2: Normal blood pressure (BP < 140/90 mmHg (or < 130/80 mmHg if diabetes or CKD) and not on hypertension medication)

• haven::tagged_na("a"): Not applicable

• haven::tagged_na("b"): Missing

Details

This function implements clinical guidelines for hypertension classification:

     **Blood Pressure Thresholds:**
     - General population: >= 140/90 mmHg indicates hypertension
     - Diabetes or CKD patients: >= 130/80 mmHg indicates hypertension (lower threshold)

     **Medication Logic:**
     - Anyone taking hypertension medication is classified as hypertensive
     - Medication status may be adjusted based on comorbidities (diabetes, CKD, cardiovascular disease)

     **Missing Data Codes:**
     - `bpmdpbps`, `bpmdpbpd`:
       - `996`: Valid skip. Handled as `haven::tagged_na("a")`.
       - `997-999`: Don't know, refusal, or not stated. Handled as `haven::tagged_na("b")`.
     - `any_htn_med`:
       - Tagged NA "a": Valid skip.
       - Tagged NA "b": Don't know, refusal, or not stated.
     - `ccc_32`, `cvd_status`, `diab_status`, `ckd_status`:
       - `6`: Valid skip. Handled as `haven::tagged_na("a")`.
       - `7-9`: Don't know, refusal, or not stated. Handled as `haven::tagged_na("b")`.

See also

adjust_sbp(), adjust_dbp() for blood pressure adjustment, derive_hypertension_adj() for adjusted BP classification

Examples

# Scalar usage: Single respondent
# Example 1: Respondent has systolic BP = 150, diastolic BP = 95, and on medication.
derive_hypertension(bpmdpbps = 150, bpmdpbpd = 95, any_htn_med = 1)
#> [1] 1
# Output: 1 (High blood pressure due to systolic BP, diastolic BP, and medication usage).

# Example 2: Respondent has systolic BP = 120, diastolic BP = 80, and not on medication.
derive_hypertension(bpmdpbps = 120, bpmdpbpd = 80, any_htn_med = 0)
#> [1] 2
# Output: 2 (Normal blood pressure as BP is below 140/90 mmHg and not on medication).

# Example 3: Respondent has non-response BP values of 996 for both systolic and diastolic.
result <- derive_hypertension(bpmdpbps = 996, bpmdpbpd = 996, any_htn_med = 0)
result # Shows: NA
#> [1] NA
haven::is_tagged_na(result, "a") # Shows: TRUE (confirms it's tagged NA(a))
#> [1] TRUE
format(result, tag = TRUE) # Shows: "NA(a)" (displays the tag)
#> [1] "NA"

# Multiple respondents
derive_hypertension(
  bpmdpbps = c(150, 120, 135), bpmdpbpd = c(95, 80, 85),
  any_htn_med = c(1, 0, 1), diab_status = c(2, 2, 1)
)
#> [1] 1 2 1
# Returns: c(1, 2, 1)

# Database usage: Applied to survey datasets
# library(dplyr)
# dataset |>
#   mutate(hypertension = derive_hypertension(bpmdpbps, bpmdpbpd, any_htn_med))