For iOS healthkit how to save systolic and diastolic blood pressure values?

Question

Here is code for saving blood pressure data in health kit

 HKUnit *BPunit = [HKUnit millimeterOfMercuryUnit];
 HKQuantity *BPSysQuantity = [HKQuantity quantityWithUnit:BPunit doubleValue:150.0];
 HKQuantityType *BPSysType = [HKQuantityType quantityTypeForIdentifier:HKQuantityTypeIdentifierBloodPressureSystolic];
 HKQuantitySample *BPSysSample = [HKQuantitySample quantitySampleWithType:BPSysType quantity:BpsysQuantity startDate:now endDate:now];
 [self.healthStore saveObject:BPSysSample withCompletion:^(BOOL success, NSError *error) 

same way for diastolic also,

But how to save both combine as single entry in health app? Currently two diffrent entries are saved for systolic and diastolic blood pressure in health app.

Answer 1

- (void)saveBloodPressureIntoHealthStore:(double)Systolic Dysbp:(double)Diastolic {

HKUnit *BloodPressureUnit = [HKUnit millimeterOfMercuryUnit];

HKQuantity *SystolicQuantity = [HKQuantity quantityWithUnit:BloodPressureUnit doubleValue:Systolic];
HKQuantity *DiastolicQuantity = [HKQuantity quantityWithUnit:BloodPressureUnit doubleValue:Diastolic];

HKQuantityType *SystolicType = [HKQuantityType quantityTypeForIdentifier:HKQuantityTypeIdentifierBloodPressureSystolic];
HKQuantityType *DiastolicType = [HKQuantityType quantityTypeForIdentifier:HKQuantityTypeIdentifierBloodPressureDiastolic];

NSDate *now = [NSDate date];

HKQuantitySample *SystolicSample = [HKQuantitySample quantitySampleWithType:SystolicType quantity:SystolicQuantity startDate:now endDate:now];
HKQuantitySample *DiastolicSample = [HKQuantitySample quantitySampleWithType:DiastolicType quantity:DiastolicQuantity startDate:now endDate:now];

NSSet *objects=[NSSet setWithObjects:SystolicSample,DiastolicSample, nil];
HKCorrelationType *bloodPressureType = [HKObjectType correlationTypeForIdentifier:
                                 HKCorrelationTypeIdentifierBloodPressure];
HKCorrelation *BloodPressure = [HKCorrelation correlationWithType:bloodPressureType startDate:now endDate:now objects:objects];
                                [self.healthStore saveObject:BloodPressure withCompletion:^(BOOL success, NSError *error) {
    if (!success) {
        NSLog(@"An error occured saving the height sample %@. In your app, try to handle this gracefully. The error was: %@.", BloodPressure, error);
        abort();
    }
    [_activity stopAnimating];
    UIAlertView *savealert=[[UIAlertView alloc]initWithTitle:@"HealthDemo" message:@"Blood Pressure values has been saved to Health App" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [savealert show];

}];
}

Answer 2

Check out HKCorrelation. A correlation is a set of related objects and is designed to represent things like blood pressure readings and food. You can save create and save correlations just like samples and you can query for correlations using HKCorrelationQuery.