Locate Patients who have multiple high blood pressure readings

dd <-  # from dput() 
structure(list(ColA = c(92L, 94L, 174L, 176L, 180L, 268L, 268L
), PT_ID = c(1900L, 1900L, 2900L, 2900L, 3900L, 3900L, 3900L),
    Blood_Pressure = c(90, 90, 140, 130, 120, 150, 90), OBS_TYPE = structure(c(1L,
    1L, 2L, 2L, 2L, 2L, 1L), .Label = c("DBP", "SBP"), class = "factor")), .Names = c("ColA",
"PT_ID", "Blood_Pressure", "OBS_TYPE"), class = "data.frame", row.names = c(NA,
-7L))
library(plyr)
ddply(dd, .(PT_ID), summarize, Include=sum(OBS_TYPE=="DBP" & Blood_Pressure>=90)>=2 || sum(OBS_TYPE=="SBP" & Blood_Pressure>=140)>=2)
PT_ID Include
1  1900    TRUE
2  2900   FALSE
3  3900   FALSE

sum(logicalVector) tells how many TRUE's are in logicalVector.

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
Of Bert Gunter
Sent: Thursday, January 31, 2013 9:52 AM
To: Weijia Wang
Cc: r-help at r-project.org
Subject: Re: [R] Locate Patients who have multiple high blood pressure readings

Well, since no one has responded....

Please use ?dput to provide data in your posts.

 There are likely  zillions of way to go about this. Following is one
way based on ?duplicated that I think works, but I make no claims for
either elegance or efficiency. Others may do lots better. But maybe it
suffices.

## Untested
## I assume the data is provided in a data frame named dd.

## All PT_ID's with >=1 high readings in SBP or in DBP
hiS <- with(dd,PT_ID[OBS_TYPE == "SBP" & Blood_Pressure >= 140])
hiD <-  with(dd,PT_ID[OBS_TYPE == "DBP" & Blood_Pressure > =90])
## id's that appear more than once in either
union(unique(hiS[duplicated(hiS)]), unique(hiD[duplicated(hiD)])
## you can subset your data frame to match just these,  e.g. via
%in%, if you like.

Cheers,
Bert

On Thu, Jan 31, 2013 at 7:51 AM, Weijia Wang <wwang.nyu at gmail.com> wrote:
On Thu, Jan 31, 2013 at 10:29 AM, Weijia Wang <wwang.nyu at gmail.com> wrote:

Hi,

I have a new question about subsetting in R.

Say we have this data frame:

    PT_ID Blood_Pressure OBS_TYPE

92   1900      90.0      DBP

94   1900      90.0      DBP

174  2900     140.0      SBP

176  2900     130.0      SBP

180  3900     120.0      SBP

268  3900     150.0      SBP

268  3900      90.0      DBP

I need to obtain those with 2+ DBP>=90 or 2+ SBP>=140.

PT_ID=1900, he has 2 DBP>=90, so he will be included.

PT_ID=2900, he has 1 SBP>=140, so he will NOT be included.

PT_ID=3900, he has 1 SBP>=140 and 1 DBP>=90, so he will still NOT be
included.

So, the condition requires TWO OR MORE values higher than the threshold.
It could be either SBP or DBP or both of them.

I have tried ddply, but I don?t know how to add the condition 2+ inside
ddply.

Any help is appreciated!!

Weijia

        [[alternative HTML version deleted]]

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--

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-
biostatistics/pdb-ncb-home.htm

______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Locate Patients who have multiple high blood pressure readings

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