Foot & Ankle International - September 2019 - 1008

1008
Through computer-adaptive technology, modern patientreported outcomes (PROs) tools like the Patient-Reported
Outcomes Information System (PROMIS) may be better
equipped to monitor for changes after surgery than traditional metrics like the GAD-7. Using PROMIS, data from
multiple patient-specific domains including pain, function,
and anxiety can be gathered efficiently, thereby allowing
for assessment of changes in outcomes following surgery
with minimal responder burden. Although used infrequently
in orthopedic studies,8,11 the PROMIS anxiety tool specifically can assess emotional distress by querying for symptoms of fearfulness, pain, and nervousness.18 Moreover,
prior work has successfully linked GAD-7 scores to
PROMIS anxiety levels with GAD-7 score of 8 corresponding to a PROMIS anxiety score of 59.4.20
In this study, we used the PROMIS anxiety measure as a
proxy for preoperative patient mental health with the goal of
understanding the influence of emotional distress (ie, anxiety) on elective foot and ankle surgery outcomes. We hypothesized that patients with higher preoperative PROMIS
anxiety scores would have more pain and worse function
than patients with less preoperative emotional distress.

Methods
Following institutional review board (IRB) approval, we retrospectively reviewed charts of all patients over 18 years old
who underwent foot and ankle surgery from April 2016 to
December 2017 by a single surgeon. A wide variety of surgery types were included. All operative procedure codes
were included and captured through billing codes. Exclusion
criteria included patients who underwent surgery for trauma,
infection, or routine removal of hardware. In addition,
patients with diabetes or evidence of neuropathy were
excluded. Demographic data were gathered via questionnaires completed by patients at or prior to the day of their
initial clinic appointment. PROMIS data-specifically, physical function, pain interference, and anxiety scores-were
captured at every clinic appointment electronically using previously defined and validated criteria.17 To briefly review, a
PROMIS score of 50 represents a population average and
10-point changes represent a SD from that average. Higher
scores in negatively worded questions like PROMIS pain
interference and anxiety represent more disability (ie, greater
pain and more anxiety) whereas larger PROMIS physical
function scores indicate greater function. PROMIS measures
from the clinic date closest to surgery were used for preoperative assessment, and PROMIS scores furthest from the
date of surgery were used as the postoperative comparison.
There were 205 patients who underwent foot and ankle
surgery during our study time frame with complete PROMIS
data. There were 59 patients with PROMIS anxiety scores
≥59.4 and 146 patients with scores <59.4. No patients
were excluded for missing PROMIS data. Our study

Foot & Ankle International 40(9)
population was predominantly female (66 females, 75% of
the total study population).
Incorporating prior evidence connecting GAD-7 levels
and PROMIS anxiety scores, we separated our study population into 2 groups, comparing PROMIS scores between
those patients with higher preoperative anxiety (PROMIS
anxiety ≥ 59.4) to patients with lower preoperative anxiety
(PROMIS anxiety < 59.4). Chi-square testing was used to
investigate for a relationship between gender and preoperative anxiety scores. Student t tests were used to compare age
at surgery, follow-up duration, and all pre- and postoperative PROMIS outcomes between these 2 groups. We also
studied the change in PROMIS scores (delta) pre- and postoperatively between groups. Statistical significance threshold was set at P <.05, and statistical calculations were made
with SPSS Statistics Software (IBM, Armonk, NY).

Results
In comparing patients with higher and lower preoperative
PROMIS anxiety scores, gender was not associated with preoperative anxiety (P = .44). Additionally, there were no differences in age at surgery or follow-up duration from surgery
(Table 1). Prior to surgery, patients with higher PROMIS anxiety scores had more pain (P < .001) and, as expected, more
anxiety (P < .001). Patients with lower preoperative PROMIS
anxiety scores had better PROMIS physical function scores
compared to patients with more anxiety (P = .001), although
the magnitude of this difference (4.1) did not meet the previously published MCID threshold (4.2).9 After surgery, patients
with higher preoperative PROMIS anxiety scores exhibited
more pain (P < .001; Table 1), less function (P < .001), and
greater emotional distress (ie, PROMIS anxiety; P < .001).
Additionally, patients with higher preoperative anxiety reported
a significantly larger reduction in anxiety postoperatively (P =
.04; Figure 1). However, there were no differences (P > .05) in
the magnitude of change (ie, delta) in PROMIS pain and function scores from before to after surgery between patients with
higher and lower preoperative PROMIS anxiety scores.
To better understand if the changes in PROMIS anxiety
before and after surgery were clinically relevant, the minimal clinically important difference (MCID) was calculated.
Using prior methodology,9 the MCID for PROMIS anxiety
was determined as one-half of the SD for preoperative
PROMIS anxiety scores for the entire study population
(N=205; average preoperative PROMIS anxiety: 52.0; SD:
10.6; range: 32.9-84.9). Based on our data, the PROMIS
anxiety MCID was 5.3
We then sought to determine if the change (ie, delta) in
PROMIS scores met this MCID threshold. For the entire sample (N=205), the change in PROMIS anxiety scores (average
delta: 6.0, SD: 10.0) met the MCID threshold. However,
patients with lower preoperative anxiety did not meet this
threshold (average delta: 5.1, SD: 10), whereas patients with

Foot & Ankle International - September 2019

Table of Contents for the Digital Edition of Foot & Ankle International - September 2019